The Bachmann Big Hauler is a
very popular engine, primarily because it is visually attractive
and they can be usually found real cheap. However, the Big Hauler
is intended to be a low cost mass manufactured engine and therefore
isn't built to be highly durable. This doesn't mean that the Big
Hauler is a total piece of junk. It takes a little work, but it can
be made to run long and well.
The Big Hauler has a 4-6-0 wheel configuration which is also called a Ten Wheeler. This engine type replaced the 4-4-0 American type in the latter half of the 19th century in fast freight and passenger service. It was larger than the 4-4-0 and could pull a heavier load. The 4 wheel leading truck allowed good tracking at fairly high engine speeds. The 2-6-0 Mogul and 2-8-0 Consolidation tended to replace the 4-4-0 in freight service.
Bachmann's model is of a generic Baldwin product. The scale of the model is debatable. Since Ten Wheelers were built by the thousands over several decades and in various sizes, the model could represent a smaller narrow gauge loco in 1:20.3 scale, or a larger loco in 1:24 scale. 10 Wheelers of the vintage modeled didn't get big enough so that the model could reasonably represent a prototype in 1:29 or 1:32 scale. There were larger and more modern 10 wheelers made, but they don't look anything like this model.
The Bachmann Big Hauler has been built in many versions over the years. I believe that the first version was the Radio Controlled Big Hauler which was produced in about 1990. This version was manufactured for many years thereafter in essentially the same form. It was never very effective as an engine, but it got many of us started in Large Scale. R/C sets could be found at toy discounters for as little as $50.
Either around the same time or a little later, track powered versions appeared. Entire sets could be found at the warehouse stores for around $100 every Christmas time. The first versions had all plastic detail, no external valve gear, very noisy internal gearing and sheet metal wiper style power pickups. The engines evolved over the years slowly gaining some external metal detail, "improved" power pickups, external valve gear, several different internal gearing arrangements, and a variety of different external details. The evolved engines were called the "Plus" series, but in fact, there were many versions of the "Plus" engines. Improvements were usually first applied to engines sold individually, but eventually these improvements made it into engines in found in sets as well.
As of October 2000, a new set, the Chattanooga Railroad, appeared at Costco stores for $90. The set has a Christmas style paint job on the engine and a couple of yellow coaches. I grabbed one on impulse and I found that Bachmann has made some serious improvements over the last few years. This one runs as smoothly and quietly as any large scale loco and is clearly worth the money. Don't expect that ALL of the Big Hauler traits have been fixed however, you'll still have to tweak on it a little.
5 Dec 08 13 Sep 09 8 Nov 08One of the major complaints against the Big Hauler is the fact that it tends to derail easily. The main culprit is the pilot truck. You can try these things to materially improve the tendency to derail.
Make sure that the truck moves and rotates freely. The most common cause of problems is that the wires that connect the power pickups on the leading truck get pinched and prevent free movement of the truck. The symptom of this is the tendency for the front wheel on the inside of turn to lift from the track. To handle 2' radius curves, the truck must be able to move freely over the full width of the mounting slot. If the wires are pinched, loosen the screws in bottom cover next to the truck and free them.
The lead truck often needs to be lubricated to slide freely. Use graphite lubricant on the sliding parts of the truck mount.
Do not tighten the long
screw near the pilot truck too tightly. If you do, it will deflect
the bottom cover some and may bind up the movement of the lead
truck. Also, the pilot truck may hang up due to an interference
between the truck pivot washer and nearby screw. If a truck wheel
tends to lift when entering a turn, especially in reverse, look for
this problem. You may have to grind down the screw head a little to
allow clearance.
Check the gauge of the pilot truck wheels. If the wheels won't slop sideways 1/16" or so you'll have to regauge them. Remove the wheels on the leading truck by pulling them off. Cut the plastic axle shorter by about 1/32" and reinstall the wheels. On some locos, they are gauged too narrowly already. The symptom of too narrow a gauge is that the wheels tend to pop up at the frog of a turnout when they can't fit around the guardrails on both rails at the frog. In this case, twist and pull on them a little to create a small gap between the plastic insulator and the wheel.
Weight the
truck. My local Big 5 sporting goods store carries 1 oz lead
weights that are shaped like a flattened oval. Use epoxy or Liquid
Nails to glue 4 of these to the top of the truck. Make sure that
whatever weight that you use does not interfere with the movement
of the truck. Check especially for interference with the frame or
the cylinder heads.
Look to your track. The Big Hauler is intolerant of rapid changes in grade. If the track drops away from the pilot truck too rapidly, the truck may actually bottom out and just hang there. When this happens, it is not likely that the truck will come back down on the track. Note that added pilot truck weights may interfere with the frame on turns if your track has vertical gradients and the pilot truck spring gets depressed. Either relieve the frame above the front pilot truck axle or fix your track.
If all of this fails, you
can completely change out the pilot truck mount. I had one 3rd
generation Big Hauler that just didn't get much run time because it
derailed every time at least a dozen spots around the layout. I
finally ripped out the stock truck mount and made my own from a
piece of brass strip stock. Now it tracks fine and doesn't derail
anywhere on the layout.
The new mount is attached to the lower cover right at the front at the natural rotation point for the truck. The original coil spring is discarded and the mounting post is cut down to 3/16" high. The new mount provides the pressure that the truck needs to stay on the track without adding friction that would prevent the truck from moving and rotating to follow the track. The mount is intended to press down on the center of the truck but not to impede its movement sideways or its ability to yaw, pitch or roll. The spring has considerably more vertical movement capability than the original mount so that the truck is much more tolerant of abrupt changes in grade.
The strip stock is
drilled for #4 hardware and bent at the fold lines. If you make
this mod, you'll have to play with the profile of the spring some,
but it will work. At the truck end, the spring is attached to the
truck with the original screw reinstalled loosely so that the truck
can slop around a lot. The original coil spring and washers are
discarded.
At the frame end, the spring is mounted with
a #4 screw and double nuts. Doubling nutting the screw allows the
spring to be drawn fairly tight against the frame but not so tight
as to prevent free rotation. The second nut is driven against the
first to lock them both in place.
There is some raised lettering on the bottom of the frame that will hang on the spring. It says "Bachmann China". This lettering needs to be filed smooth.
If you've used the weights as described above, you'll need to remove the rear ones. I removed all 4 and the truck still tracks properly.
I extended the power wires about an inch to allow them to loop loosely so that the wires don't apply any forces to the truck at all. The wires come back out the original mounting slot.
Barry Olson of Barry's Big Trains sent me an
evaluation version of his replacement pilot truck for a Big Hauler.
The method I described above is actually a variation of this
modification, but Barry provides a whole new truck frame that is
much "floppier" than the stock Bachmann truck and can follow really
bad track better. I had one last unmodified Big Hauler so I ripped
off the stock pilot truck and installed this one. It was pretty
easy but I did make some changes.
Barry recommends drilling the mounting hole for the pivot arm 7/8" back from the front of the bottom cover of the Big Hauler. I found that I had to drill the hole 1-1/8" back to get the truck centered on the cylinders.
He also recommended drilling a new hole to route the wires from the truck back up into the loco. I elected to route them back up the curved slot. To do that I needed to cut the tie wrap that he provided that attaches the harness to the arm.
Barry provided two new spacers for the pilot wheels. These were so tight that I didn't use them. I reused the old ones that had already been cut down in length to regauge the wheelsets.
The frame
members of Barry's kit are metal but they are provided with a
non-conductive coating. This coating prevent current transfer from
the wheels to the frames. This coating would eventually wear off in
the right places, but I cleaned it out with a Dremel tool and this
small wire brush. After cleaning the accumulated gunk off the wheel
shanks as well, the power pickup from the truck was quite good.
The result was a pilot truck that seemed to be able to ride over pretty much anything. There were ivy leaves and stems on my track when I did the initial test run. The pilot truck went right over this stuff which eventually derailed the tender several times. The pilot truck never did derail anywhere. However, the new truck is so light that it is susceptible to undergauge track or overgauge wheelsets. If the flanges don't fit between the rails properly, they will be squeezed up and derail. If this happens with properly gauged wheels, then fix the track.
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The Big Hauler is notorious for having flaky power pickup. The engine is supposed to pick up power on 8 wheels, but in fact the leading truck doesn't contribute much. This leaves four the drivers and they get flaky too. Bachmann has made three different types of power pickups, sheet metal wipers, spring loaded contacts and brass wheel bushings. While the brass bushings are better than the others, they develop problems too.
Old Style Wiper Contacts. If your engine is an old one with strips of metal bent to make wipers, they may be completely worn out or the glue that holds them to the side of the frame has probably let go so that they have lost contact force. Either way, the best bet is to scrap them and install LGB contacts. Then add metal wheels and contacts to the tender. If the original ones aren't actually worn out, they probably still don't touch the wheels at the extremes of the axle play.
On the older
engines, I glue strips of styrene to the outsides of the frame
right above the axle slot to limit the side play so that the
contacts have a chance of making contact. I find that it takes
about 0.1" of shim on each side to control the axle play.
Piston Style
Contacts. If your engine has spring loaded contacts, you
still might want to shim the drivers as the contacts still don't
reach all the time. However, a better solution is to trash the
Bachmann contacts and install LGB contacts and then shim the axles.
The Bachmann contacts heat under heavy load and the spring looses
tension. On this engine, a spring actually melted the contact
housing. To entirely replace a contact, pull out the Bachmann
contact and unsolder the wire from the back. Then solder the wire
to the end of an LGB contact and then install it in the original
hole with a glob of hot glue or your favorite structural adhesive.
These contacts will last a long time and don't heat much when
loaded.
Bushing Style Contacts. The
third style of power contact uses the wheel bushings to provide a
connection to the wheels. The bushings are connected to the engine
with spring contact fingers mounted to the lower cover. The front
truck pickups are wired to these contact springs as well. The wires
to the engine body plug into the contact strips so that
disconnection or reversal of the power contacts is easy.
All is not well with this new system however. I noticed a pronounced sensitivity to track condition after several hours of running and a couple of disassemblies. One of the spring contacts had become cocked slightly and it rested on an insulator on the rear axle instead of the bushing. Further, the bushings seem to be flakey. There is a wheel position related hesitation on both axles when the engine is run from a Kadee wheel brush. During the hesitation, the engine makes spitting and growling sounds which may be related to motor thrashing while the resistance of the bushing is changing. The engine runs completely smoothly when the brush is used on the pilot wheels.
I isolated the problem to the bushings by connecting directly to the bushing and the wheel. Other than using a conductive oil on the bushings, there doesn't seem that there is much to be done. Perhaps Bachmann will use a ball bearing on the next version as these seem to work fine on locos from other manufacturers.
Tender
modifications. There isn't any convenient place on the
tender trucks to mount power pickups. I epoxied a 1" square piece
of styrene to the bottom of the truck to make a platform where I
could epoxy LGB contacts. Solder wires to the contacts before you
epoxy them down as the heat of soldering will soften most epoxies.
Connect the new contacts back to the engine with some sort of small
connector. You might have to rummage around a local electronics or
R/C car store to find something suitable or use the method
described in the Power
Connector Tips page.
There is a cheaper
way to add power pickups to a Big Hauler tender that already has
metal wheels. Bachmann metal wheels have two drilled pits on the
backside of the wheel that make them unsuitable for piston style
contacts. However, a simple piece of bent brass strip stock will
slip over the truck and contact both wheels. It will even hold
itself in place if the strip is 0.25" wide so that it captures
itself between the truck frame and the wheel flange. I used 0.016"
thick stock, but thinner stock will do as well. If you have it, thinner BeCu stock would work better as it has more "spring" to it and it would be easier to get adequate pressure with less drag. The downside of
this cheap and dirty technique is that it adds drag, something that
Big Haulers can ill afford. However, even conversion of one truck
materially improves the power pickup performance. This modification
is completely reversible as there are no modifications made to the
structure of the tender at all.
Leading Truck. There doesn't seem to be much that can be done to improve the pickup from the stock front truck except by using conductive oil on the bearings. Make sure that the wires are not broken.
There is an aftermarket front truck available from Barry's Big Trains, see the section above about derailments. This truck has better power pickup than the stock truck once you clean the paint out of the axle bushings.
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There are at least SIX different motor/gearing systems in use in Big Haulers. The later versions have the motor mounted in a metal bracket with the gearing. I don't have a 4th generation loco, but from reports from the field this one seems to be more robust than the earlier versions. Even so, I've still heard of the gearing getting mangled. Engines with this gearing will have a bulge on the bottom cover right between the rear drivers. This bulge clears the larger gear needed on the axle so that a reasonable reduction ratio could be achieved without intermediate gearing. The 5th generation has an intermediate reduction gear and a more substantial gearbox This version seems to be holding up well in real life service. The 6th generation is the "10th Anniversary Edition" (aka "Annie") version. I don't have one of these, but reports from the field indicate that it has the same gearing as the 5th generation drive, but with a 7 pole motor. The 7 pole motor allows it to run more smoothly at very low speed.
The R/C Big Hauler uses a gearing
system that is similar to the early track powered version, but it
has a smaller lower voltage motor. I refer to this gearing as the
1st generation as I believe that this was the first kind of Big
Hauler marketed.
The early
track powered version (2nd generation) uses the same gearing as the
first generation but it has a larger motor. Due to all these gears,
these make the most noise. In my limited experience the gears don't
seem to strip as much as the 3rd generation type. The version has a
large gear reduction ratio so that the motor runs fast (hence lots
of noise) but this also reduces the load on the motor itself which
tends to allow it to draw a little less current than the later
versions. This engine runs fine on the puny power pack that is
included in the Big Hauler sets. The later versions, especially the
3rd and 4th generations, tend to really tax the little power pack
as the motors on the newer units run at higher shaft torque, lower
motor speed and therefore higher motor current.
The 3rd generation version
uses a brass worm on the motor and plastic reduction gears. These
seem to the most prone to wiping out the gearing. Worm gears, when
placed under load, tend to thrust perpendicular to the motor shaft.
If the motor is not mounted firmly (see below), this thrust tries
to make the worm walk over the teeth on the meshed gear. This is
evidenced by a clear popping or clicking noise, particularly when
running loaded in reverse. This version was produced from the early
90's to about 1997 so the majority of Big Haulers out there,
including many of the "Plus" versions will have this type of
gearing.
I don't have a 4th generation Big
Hauler, but Dan Pierce sent a photo of his. This one uses a worm on
the motor and a single gear on the axle. The motor and rear axle
are held in a bracket made from a piece of sheet metal bent into a
U shape. The axle gear is fairly wide and centered on the axle.
There is a bump on the lower cover to clear this gear. The bump is
also centered.
This version should have had a lower gear failure rate, but it didn't appear to work to well. There have been many reports of this configuration eating its gearing under load.
The 5th version is
shown in the photo. This version appeared sometime during 2000.
This one has an intermediate reduction gear and a more substantial
metal gearbox assembly. The axle gear is narrower and offset from
the center. The bump in the lower cover is also offset from the
center.
There have been reports that this version has a tendency to slip. The large axle gear is apparently not attached well enough to the axle and can slip on the axle. Mine has not done this, but those with the problem have reported that if a hole is drilled in the plastic bushing next to the large gear and right through the axle and the bushing on the other side and a pin is inserted, the axle then becomes locked to the gear. The hole should be just large enough to clear the pin. A piece of steel wire would work. Then ends should be folded down to capture the wire.
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A common problem with Big Haulers is stripped gears. There are a variety of causes, but a major one is that the motor mount is inadequate. Other causes are heavy loads in high heat and inadequate lubrication. I can't recommend much about operation in high heat except maybe don't do it, but the other problems can be fixed.
In the earlier versions, the motor is held in by two mechanisms, neither of which is adequate. Glue holds it in place, that is until the motor heats up and the glue lets go. Also the motor is pinched in saddles. Unfortunately, one of the saddles is in the bottom cover which is not very stiff. Under heavy loads, the whole bottom cover will flex in response to motor loads and the motor squirms around.
For those of you that have
the gearing with the brass worm and multiple reduction gears (3rd
generation), you should make this modification to the motor mounts
or you probably WILL strip some gears eventually.
The earlier versions without the brass worm don't seem to need this
modification, but it won't hurt. The 4th and 5th generations don't
seem to need this modification either.
Open both the top and bottom of the engine and wrap a long heavy duty cable tie around the motor and the iron weight mounted on top of the frame as shown in the photo above. Cinch that sucker down TIGHT. This holds the motor in the frame half of the saddles and materially improves problems with stripped gears. This is most important on the types with a brass worm gear and multiple nylon reduction gears.
Now that I've recommend that you cable tie the motor, you MUST make sure that you have the new motor mount ring. The new motor mount ring is a white plastic ring that wraps around the motor bearing on the worm end. This part can be clearly seen in the photo. The old type is yellowish clear plastic and is much softer. If you cable tie the motor down with an old ring, the ring will slowly deform and the worm will bear hard against the first gear. This increases the load on the motor and wears the gears and bearings out much faster. If you have an old style ring, write Bachmann and ask for a new one, they'll send it out free.
If you already have stripped gears but the rest of the engine is intact, send Bachmann the bad gears and they'll probably send new ones back for free.
I've probably had better luck than many people with Big Hauler gears because my engines lead a sheltered life. They always stay in a cool basement which never gets warmer than 60 F. This is a far cry from sitting on the ground in Phoenix in the summer where the ground level temperatures can exceed 140 F. At these temperatures, the plastic gears will soften and be much more susceptible to being mangled.
Even so, I spun the gear on the driver axle on an old Big Hauler. This happened after I added weight and could pull a heavier load. It was a simple matter to repair the gear, almost in place. I slid the gear off the knurled section of the axle and then coated the knurling with a filled epoxy. I then slid the gear back over the knurling to the proper position and allowed the epoxy to set. The epoxy grabbed on the knurling and on the ripped up plastic that had slid on the knurling and mechanically bonded the gear back on the axle. This patch has not given me any more trouble in 13 years of blatant abuse.
I think that one of the basic reasons for Big Haulers stripping gears more often that other locos is that there is only one gear train to take up the load. Other locos usually have 2 or 4 gear trains so that the stresses placed on those gears are proportionally less. Add this to some heat and sloppy meshing and disaster is very likely.
The Delton C-16 had only one drive gear and it has a reputation for stripping and wearing gears too. BBT's Bachmann conversion also has only one gear train, but it is an industrial strength system and doesn't seem to suffer the same difficulties.
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The Big Hauler was made in a R/C version. This engine looked externally identical to an early track powered version but ran from internal batteries and a rudimentary radio control system. The engine was available only in train sets.
The R/C gear is a simple AM system that operates at 27 MHz although there may have been some 49 MHz systems out there as well. If the engine ran out of range of the transmitter, it would run at its default setting of full forward until it came back into range. This made backing moves difficult as the engine would try to go forward every time it lost its RF signal which would often result in severe bucking.
When working properly, the motor control system is very effective. The engine can be nudged along at very low speeds and it runs steadily, that is as long as you are close enough to the engine to prevent it from running away.
The R/C receiver is mounted on a circuit board in the smoke box and is a little difficult to get to. The antenna wire runs down the left side of the engine and loops through the cab. It has to be disconnected at a screw terminal about halfway along the left side of the boiler before the shell can be removed.
The RF receiver circuits take up roughly the front 1/3 of the circuit board. The H-bridge motor controller takes up the center 1/3 of the board and the sound system takes up the rearmost 1/3 of the board. The wire leading to the tender carries the signal to the speaker. In a track powered Big Hauler, this wire carries the pulses from the sound switch.
The R/C Big Hauler is designed to run from 9 volts generated by six internal D batteries. These batteries also give the engine quite a bit of weight and with the traction tires, the engine can pull fairly well on good batteries. However, the engine can also flatten the batteries fairly quickly. There is an adapter cable included to use an R/C car type sub-C rechargeable battery pack. The voltage of the sub-C pack is typically 7.2 volts so that the engine runs a little slower on the rechargeable battery than a good set of alkaline batteries.
The R/C Big Hauler has another problem. Its plastic drivers are intended to run on plastic track. After extended running on tight radius metal track, the flanges will get roughed up and eventually, they will generate so much traction against the rails in turns that the outside rear driver will literally climb the rail and derail. As much as I tried, I couldn't get the wheel resurfaced adequately so I replaced the drivers with a metal set that was made for the same vintage track powered Big Hauler. The gearing was identical so it fit right on. However, the downside is that for some reason, every time the engine ran in reverse over a turnout, some sort of radio interference was generated and the engine tended to try to reverse and buck. I never did fix this problem, we just had to stay near the engine so that the radio signal was fairly strong. We did find that by touching the transmitter antenna to the track, that the track tended to conduct the radio signal to the engine and it did run better.
The R/C Big Hauler was not equipped with smoke, but I found that the smoke stacks themselves make an excellent replacement oil stack for a Bachmann Shay. The stack needs to be filed before it will fit, but once in place and airbrushed with a light coating of engine black, it matches the Shay smokebox color very well. The sound generators also transplant into a Shay well and produce a credible chuffing sound for considerably less investment than a digital sound system.
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Proper lubrication is critical in maintaining a Big Hauler's health. Every few months, you should follow a lubrication schedule.
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If your Big Hauler is really too far gone for remedial work, you have several options:
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Barry of Barry's
Big Trains sent me a set of his new laser cut stainless steel
siderods for the Big Hauler. He makes these because the Bachmann
siderods sometimes don't fit his mechanisms due to some rather poor
tolerance control at the Bachmann factory. After looking around for
an engine to install them on, I realized that none of my engines
really needed them. I did test fit them on an R/C Big Hauler and
found that they fit fine. I put the old rods back on because it
didn't seem right to put such a nice set of hardware on an engine
that hardly runs anymore. I'm going to save them for an eventual
BBT chassis upgrade.
Barry also sent me a set of metal crosshead guides. These are
intended to replace the ones that so often break off Big Haulers. I
didn't install these either but I did overlay them on a couple of
Bachmann engines and it looks like they would fit well. Some Big
Haulers have bumps on the stock plastic guides that cause the
engine to click as it runs. These parts would fix that.
Barry also makes a replacement front truck, see the section above about tracking and derailments.
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The Bachmann sound system can be inexpensively upgraded to sound much better. An article (Feb. 98) in Garden Railways Magazine describes the three upgrades to the stock Bachmann sound system. You can also find a draft of the article at Better Big Hauler Sound for Under a Buck.
The wire between the engine and tender usually becomes very stiff with age or in the cold and the connector can tend to pull out in turns or it may even tip the engine or tender. This can cause the sound to become intermittent or stop altogether or it can cause derailments. I replace it with fine gauge speaker wire. You can get the old contacts out of the connector shell by using a fine point tool to depress the clips that hold the contacts into the shell. It is easier to do it if you cut the old wire and strip off the sleeving so that you can tug on the old wires individually. If you don't pull the contacts out of the shell, then leave a half inch or so of wire in the old shell and splice on a new flexible wire.
For those of you that haven't bothered to trace it out, here is my interpretation of the schematic of the sound generator in a Big Hauler. This same circuit is included on the rear third of the circuit board in an R/C Big Hauler.
As of sometime in 2000, Bachmann has changed the sound board. The new circuit can be identified from the outside of the tender as it has a volume control knob underneath the tender floor. It no longer will blow a continuous chuff when stopped, but the chuff profile is poor, it's decay is way too long. This can be fixed, see Better Big Hauler Sound for Under a Buck for more info.
The new board seems to have some leakage that will flatten the battery over a period of a few months. If you are not going to use it for awhile, it might be best to turn it off with the volume control under the tender.
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If the smoker works, but smokes weakly, it may be possible to improve the smoke output at zero cost, see my Smoke Tips page for details. The downside is that it may go through smoke fluid faster and be even more likely to burn up if it runs dry.
The Bachmann smoke system tends to burn up fairly often, so if you like smoke, you are better off replacing the smoke generator with an LGB unit, see Smoke Tips for a little more information on the smoke units. The Ten Wheeler smoke generator is similar to the one in the Shay, and the same modifications can be done.
There are a couple of differences between the Big Hauler and the Shay. The Ten Wheeler smoke unit is fastened from the bottom so you have remove the shell to remove the smoke generator. Also, the stack on some units is just a little too small to accept an LGB smoke unit so you will have to drill it out. A 3/8" drill is just right, the smoke unit body will drop through and the lip on the top will hold the unit right at the top of the stack. The Shay had a conveniently placed hole in the heat sink to allow the mounting of the regulator IC, on the Big Hauler, I had to drill a mounting hole. Other than that, the modification is essentially the same as for the Shay.
If your stack has a "final" on the top it may not fit properly with an LGB smoke unit installed. it can either be discarded or ground down to clear the lip of the LGB smoke unit.
If your Big Hauler has a funnel stack, you'll have to figure out the mounting yourself. I don't have a funnel so I haven't worked out the details.
This is the circuit that I
used for the Big Hauler smoke upgrade. I wired it to improve the
brightness of the headlight too. My headlight had burned out so I
replaced it with a grain-of-wheat bulb (Radio Shack 272-1092c).
This is a 12 volt bulb so it needed a 47 ohm resistor in series
with it to drop the voltage at the bulb to about 12 volts so that
it wouldn't burn up immediately. You may also need a resistor in
series with the Bachmann bulb if it burns too bright. You could
also use a 5 volt Grain-of-Wheat bulb and wire it at the output of
the regulator. You will then have to wire the smoke switch directly
in series with the smoke unit so that you can shut off the smoke
without turning off the headlight.
If your Big Hauler smoke unit is still working, you can just add the part of the circuit to the left of the switch and your smoke will run better at low speed with PWC. However it will also be at more risk if you should let it run dry.
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Bright white LEDs (Light Emitting Diode) are available that are much brighter than most incandescent bulbs used as large scale locomotive headlights. This section describes changing the headlight in the circuit above to an LED.
The Big Hauler on the left has a
Radio Shack 12v 60 mA Grain-of-Wheat bulb running at its ratings.
The Shay on the right has the stock Bachmann bulb that came on the
early production Shays, later Shays have a much more wimpy standard
yellow LED as a headlight. You can see that the Big Hauler light is
not very bright as compared to the Shay.
This photo shows the same two
engines after a bright white LED has been installed in the Big
Hauler. The LED is running at its rated 20 mA vs the 60 mA that the
old GOW bulb took. Now compare the brightness of the two locos
using the Shay as a reference to see how much brighter the white
LED is.
This is the modification
that was made to the smoke circuit above. The LED runs off
rectified track power and its current is controlled with a large
series resistor that approximates a true current source. The right
value for the voltage available is 600 ohm. I got the value by
paralleling two 1200 ohm resistors. With Aristo PWC on th track,
the LED comes on very bright before the engine even starts to
move.
The LED is
installed in place of the original lamp, but it has to face forward
to project its beam. The LED leads are insulated with shrink tube
and one lead is pressed into the original support. The support had
to be drilled out just a little to accommodate one lead and its
shrink tube. The other lead goes into the boiler just in front of
the support. A dab of hot glue holds the LED in position.
The headlight housing can just
be pulled off the loco. The LED wouldn't go into the housing until
a little gouging was done. The original hole is drilled out to 1/4"
and another 1/4" hole is drilled in front of it so that the two
holes merge together. The resultant shape is then filed out to an
oval. This allows the LED housing to slip up inside the headlight
housing.
The hard blue color of the LED can be toned down a bit by painting the LED housing with a very thin coat of Tamiya Clear Yellow paint. Keep the layer VERY thin, dry brushing or airbrushing works well. The yellow paint cuts the blue color. If you use too much the light will be distinctly yellow or even green.
[ Top ]
The Big Hauler is designed to be cheap to manufacture so its fairly easy to put together and therefore, it is easy to take apart.
[ Top ]
Bachmann has come out with a new low cost set ($89.99 in Oct 2000
at Costco while they've got them) with a significantly upgraded
locomotive. The set has the same coaches are previous sets, the
same light duty track and the same wimpy power pack (but with no AC
output terminals). There is an engineer figure in the cab. A
fireman figure, a comic book style instruction book and a VHS video
are also included. All the wheels in the set are metal.
The new loco pulls only marginally well, but due to the new axle bushings and improved gearing, it might be able handle increased weight for better traction. The results of some testing can be found on my Tractive Effort Tests page. The engine draws less current that most locos making it a good candidate for battery power.
The locomotive detail is improved as well. All the grab irons are brass rod and there is a Walsharts type of valve gear installed. The headlight is unchanged, as is the smoke unit. The tender still has all plastic details.
The sound system in the tender has been "upgraded" too. It now issues a timed chuff when it is triggered so that it will no longer stop with a chuff constantly blowing. However, the decay time of the chuff is way too long so that the chuffs tend to blend together at high speeds. This is easily fixed, see Better Bachmann Sound for About a Buck for instructions.
The
set comes packed with the loco, a combo coach and an observation
coach (without drumhead). Both the coaches are lighted using the
standard 9 volt battery. These coaches eat up expensive 9v
batteries fairly quickly. Since the wheels are metal and the pickup
pockets are still there, the lighting can be converted to track power
fairly easily.
A similar set is available at Sam's Club for
$99.99. I haven't seen this set (the photo was provided by Lou
Grandieri) but the Bach-man says that the set has the same new
mechanism as the Chattanooga Railroad set. The engine doesn't have
the external valve gear but the paint job is much better, less work
will be required to convert the road name and weather the loco. I
also understand that Orchard Supply Hardware has yet a third
special set for a similar cost.
The mechanism in this loco is all new, at least
to me. The troublesome wheel contact wipers and plungers are gone,
replaced with metal bushings on the axles that both pick up power
and support the locomotive. These bushings are substantially
heavier duty than the plastic bearings in former Big Haulers. The
bottom engine cover is electrically connected to the loco with two
small plugs so that the entire cover can be removed and placed
aside during loco maintenance. This also means that the power
pickups can be disconnected easily for a battery power conversion
without making any permanent modifications to the engine.
The locomotive
gearing is also substantially upgraded. It is now a two step
reduction gear system enclosed in a metal frame. The motor is also
attached to this frame so that the problems that the older locos
had with gear alignment may be solved. The gear train runs nearly
silently.
When I had the loco open for lubrication, I checked the minimum speed. Unloaded, the drives will turn at 6 RPM at only 0.9 volts DC. This is the lowest starting voltage that I have measured so far on any loco. The mechanism would actually run as low as 0.7 volts, but it would not run consistently.
This loco
had an audible tick in the valve gear, once per driver turn. I
tracked it down to a mold mark on the inside of the lower
crossguide on one side. The mark is about halfway down the length
of the crossguide, also about halfway between the crosshead and the
little sliver of plastic in the photo. The crosshead would pop over
the mark and make a click. A little careful file work removed the
mold mark and the tick.
I have converted the GIRR Mtn Div to operate
on DCC as well as DC track power. As more locos are converted, the
DC system is used less and less. My oldest loco is this ATSF Big
Hauler, a 2nd generation unit. As of this writing, this loco has
been running on the Mtn Div for 18 years. I didn't expect it to
last this long but it has held up well so I invested $16 in a HO
sized decoder for this loco. The 2nd generation units use a smaller
high speed motor than the later units. The high motor speed and
multiple stage gearing creates a fair amount of gear whine, but it
is not overwhelming so I still run the loco. Because of the smaller
motor, this loco draws the least current anything I have except the
Bachmann railtruck which won't pull anything. The Big Hauler handles
it's assigned 3 coach set quite nicely on the 4.2% grades of the
GIRR. It struggles on the 5.2% grade of the spiral but it does it.
Because of the low current draw, I could use an inexpensive HO
decoder, a Digitrax DH123D which is rated at 1.5 amps, this loco
only draws half that.
This
is what it looked like underneath before I started. The transistor
and diodes are an add on kludge to stop the chuff when the track
voltage goes to zero, see Better Bachmann Sound for About
a Buck for the details of this hack. The drivers have been
pulled to reveal the motor connections. The tabs from the motor are
soldered directly to the brass strip that is used for the power
pickups in this version. The wires leading forward from those
points are for the pilot truck and the headlight/smoke unit. The
brown wires lead to the back go to additional connectors that I
added to allow the tender to pick up power as well and feed it
forward the the engine.
DCC installation requires that the motor terminals be isolated from all other wiring so I had to desolder this mess and then bend the motor leads out of the way and then attach new wires to them, properly insulated.
HO
decoders are convenient because they are small. This one is just
stuffed into a pocket near the drawbar. The green and purple leads
in the harness are not used in this decoder and don't go anywhere
so I didn't insulate them. The red and black wires go to the power
pickups. The orange and gray wires go to the motor. The blue wire
is about +14 volts. The white and yellow wires are the forward and
rearward headlights. I didn't use the yellow one so it is insulated
and stuffed into the harness with the rest of the wires.
The
little sound cutoff kludge had been connected to track power, but
that wouldn't work with DCC because there is track power on all the
time. It was reconnected to the motor so that it could detect when
the loco was moving or not.
The headlight had already been converted to a white LED, but it was connected to the modified smoke circuit. I disconnected it and reconnected it from the blue wire (+) to the white wire (F0f) retaining it's 1K ohm current limiting resistor. Now the headlight is directional and can be turned off remotely.
The DCC conversion on this loco went quite well. It runs more smoothly than before at low speed because the constant high track voltage makes the loco less sensitive to variable resistance in the power pickups, of which this loco has a lot. It still makes the same gear noise, but that should not have changed. It still pulls it's assigned consist the same as before. The maximum speed is a little higher than needed, even at only 16 volts on the track. I'll wait to see how all of the locos perform at the top end and if they all end up with too much speed, I'll reduce the track voltage until the slowest one is fast enough. Then I'll change the decoder parameters of each loco to set it's individual maximum speed to just what I want.
The next one that was in line for a
DCC conversion was a 3rd generation Big Hauler, an Emmett Kelly
circus engine. This one has been has been seen before in several
places on this page. A 3rd generation Big Hauler has less gear
reduction than the 2nd generation unit. It makes less noise, but it
also needs more motor torque, and therefore draws motor current.
The running current is about 1.5 amps which is the limit for the
DH123. The stall current is nearly 5 amps, way beyond the DH123's
capability. I elected to install a DG583S decoder which is plenty
of capacity for this engine. The downside of the DG583S is that it
is bigger and considerably more expensive, about $54.
This installation required access from both the top and the bottom which made it somewhat more complicated.
The
loco used a different method of power pickup so that there isn't a
brass strip running along the side. There are piston contacts and
the first and third driver sets. The motor tabs are used as binding
posts to bring together the wires from the pickups (2 per side) the
wire to the smoke box (1 per side) and a wire to the pilot truck (1
per side). I also noticed that the bearing support ring for this
end of the motor was missing. I found it stuck in a wad of grease
inside the loco. Apparently, I had dropped it while I was putting
in the motor the last time I was in there.
I removed all four wires from one motor tab and soldered them together (with the lead from the rear contacts extended to make some working room) with yet another wire that was directed upwards in the loco body to provide power to the decoder. I then did the same thing on the other side. I then cut the tie wrap that was holding the motor in place and removed the motor. It was easier to solder new wires on the motor tabs with the motor out of the loco but the main reason for removing the motor was to reinstall the bearing support ring. I also soldered the wires to the sound system cutoff kludge and then insulated the motor tabs. The new motor wires were also directed upwards into the boiler.
The blue/yellow pair is the motor connection. Not visible in this
photo, there is also a red/black pair for track power. The darker
blue and green wires are the extensions of the wires from the rear
pickups. All of the track power wires are joined up behind the
sound system contacts and insulated with shrink tube. Removal of a
bunch of wires made the area next to the motor much less
congested.
The
decoder is mounted on top of some lead fishing weights. I had to
pull off three 2 oz. weights to make room for the decoder so that
it would not interfere with the inside of the boiler. Two of the
missing weights were attached along the sides of the stack and one
was reattached behind the decoder.
The only function wires that I used were for the headlight, the blue wire for power and the white wire for the F0f function. As with every installation of the DG583S that I have done so far, the front headlight came on only in reverse according to the icon on the throttle. I set CV29=7 to reverse the normal direction of travel (NDOT) and then swapped the motor wires so that the loco ran forward when the headlight was on and the throttle said that the loco should be running forward.
After reassembly of the loco, it ran fine with no obvious performance difference except that the low speed stability of the loco was significantly improved due to the BEMF capability of this decoder.
The 3rd generation DCC installation
went ok so I decided to attack the 5th generation Big Hauler next.
This one has had the least modification of any of them but it still
has sound updates and a remounted pilot truck. Power pickup has
also been jumpered from the tender to the loco. This one doesn't
draw quite as much current that the 3rd generation unit, but still
too much for an HO sized decoder so I put another DG583S in this
one.
The
motor mount and gearing are quite different in this loco. The motor
assembly does not come out easily. It looks like there is a pin
that holds the assembly in place. It didn't budge with some
moderate tapping so I elected to rewire the motor in place.
The motor tabs were used for a binding post, but there are
only two wires soldered to each tab. One wire comes from the bottom
cover assembly, the other goes forward to the switch on the
smokebox door. I unsoldered the wires on the top tab to get them
out of the way and then I unsoldered the wires on the bottom tab.
The wires going forward can be pulled off the tabs with a pair of
thin needle nose pliers pulling on the wires as they transit the
area under the sound switch contact strips.
I spliced the wires back together and insulated them with shrink
tube and pushed the excess up into the boiler.
The motor wires were soldered back on the motor tabs and then the other end of those wires were pushed back up into the boiler. I reassembled the bottom of the loco and buttoned it up.
The installation on the topside was pretty easy with only one
difficulty. Nothing would stick to the cast iron weight so I could
not mount the decoder up there. Even after being cleaned with
alcohol, brushed with a wire wheel and then filed down to bare
metal, my foam tape, hot glue or quick grab glue would not adhere
to the cast iron.
I punted and dropped the decoder into a cavity in the frame at the front. I insulated the connections on the smoke unit because they would come close to the edge of the decoder.
In the previous installation using the DG583S, I had difficulties with the headlight not working in the right direction. On a hunch, this time I wired the front headlight the F0r, the yellow wire for the rear headlight. Then it worked properly. Further the yellow wire responds to CV49 which sets up special effects for the FRONT headlight which is supposed to be on the white wire. Something is wrong in either the decoder firmware or the cable harness and instructions that define the front and rear headlight function wires.
I finally got around to converting a 3rd
generation Pennsy Big Hauler to DCC. This one has had most of the
standard modifications already, 4 chuffs/turn, chuff stop, sound
board mods and a weighted front truck.
I purchased some MRC
AD322 decoders on closeout at $11 each and I had two left and
nowhere for them to go so I stuff one in the Big Hauler. It was a
pretty standard installation with only the motor and the headlight
connected to the decoder. Except for the physical mounting of the
decoder, I used much the same method as the Emmett Kelly Big
Hauler. The decoder is pretty large but I found a place for it in
front of the cast iron weight. The board is held down with two
globs of hot glue at the front. The heat sink of the regular IC
rests on a piece of a coffee stirrer that is stuck to the weight
with double back foam tape. This IC gets pretty hot in operation so
I couldn't just rest it on the tape or it would have melted right
through. Just for safety, I also laid a piece of tape across the
terminals of the smoke unit to act as an insulator although the
decoder board doesn't get very close to it.
There was one change I
had to make due to an issue with the AD322. This decoder has a much
lower switching frequency than the decoders I used in the other Big
Haulers. Some of this motor noise coupled through the chuff stop
circuit and got onto the chuff sound as an audible buzz. I added a
resistor and a capacitor to filter out this noise. The 100 ohm
resistor limits the peak currents that can charge the capacitor,
this is to make the circuit more friendly to a DCC decoder. The
filter capacitor charges up to the peak motor voltage at the first
motor pulse to activate the circuit as well as filtering off the
PWM noise delivered to the motor by the DCC decoder.
© 1997-2009 George Schreyer
Created Oct 5, 1997
Last Updated September 13, 2009