Won't operate

[clcurry]

I have 2 Bachmann n scale locomotives that when placed on the track they have power, everything lights up but doesn't move, won't go forward or backward. When I place my finger on the engine I can feel that it's on but doesn't move. Any suggestions as to what might be causing this & how to correct it? Thanks!

[Ken G Price]

Not much information. Are they DC or DCC? Are you using DC or DCC for the power source?
If DC are you sure you have the DC side of the power pack wired to the track and not the AC side?

[GG1onFordsDTandI]

New? Old? New to you? Used to work? dcc or plain-old-train style? First is power transformer type to train correct? If your not sure thats first. If guessing always try DC volts first. AC, even at the same voltage, can cook a DC motor in a flash and lots of AC motors and electrical stuff can run on DC too(not all).   I dont know much about n steamers, except because of the drive wheel setup and drive linkage they can be complicated and very different. But a diesel, with finger tip LIGHTLY, DONT FORCE, but rub drive wheels. They are geared and should not want to spin. If they grind,skip, or spin free, the gears and/or driveshafts are very suspect. Get the bodyshell off, if you have modern electrical circuit boards inside its a dcc engine and I am of little help electrically from here. No boards? Put on track, power up and look into slots in chassis with a light & magnifying glass, look for motor/gear shaft turning. Does motor spin? No? Decide if your capable of fixing something this small first! No? Contact Bachmann service dept. If you feel brave, have good eyes, small tools, and a steady hand spilt the chassis(I do this in a container with high sides to prevent loss of tiny parts), remove motor & jump with power to check for spin. Assuming your motor turns under power, check driveshafts, many drive shaft u-joints have ball on each end of the shaft, each with two nubs. The motor shaft and gears have a small cup with 2 opposing slots on its sides. Line up nubs into slots, the driveshaft ball fits into the motor shaft cup, forming a ball and trunnion style CV(u-joint) The driveshaft nubs can shear off or wear out kinda easy, check um. If the motor spins, and shafts are o.k., check the gears on the truck. The gears can be spun by hand after removing driveshafts(SPIN GEARS-NOT WHEELS) Some times motors slide fore/aft and drive shafts pop out of the cups(shim to stop slide,get longer shaft), or gears/cups centers loose their grip on the driveshaft or wheel axle(replace), some gear mounts crack and they get misaligned(replace truck), sometimes dirt, ballast, etc. get in and jams them(never too clean). It doesnt take more than 1 grain of sand to stop these little suckers dead. When you do reassemble, watch your truck power pickups they belong under chassis pushing body/chassis up away from the truck.(on most) Dont rush, disassemble slow, use your eyes, try to note all the little details BEFORE its apart. At this size each chassis design engineer kinda follows their own path. Lots of similar but different approaches.

[Desertdweller]

GG1's post is a good example of an advantage of DC over DCC.  Troubleshooting is a matter of checking things you can see and physically get your hands on.

Just going by your description, if you are not using DCC, I strongly suspect you have your track power leads hooked to the AC side of your power pack.  This would cause your motor armature to vibrate but not spin.  While one defective DC motor might do this on DC, it is extremely unlikely that two would.

GG1 has given you good advice.  I only have a few things to add.  First, if you take the split frame apart, remember which side of the motor faces up.  Put it back in the frame incorrectly and it will run backwards to your other loco as the polarity of the field magnets will be reversed.

Also, split frame locos are extremely sensitive to spacing and screw tension holding the halves together.  Don't lose the spacer washers, and keep them so they will go back in the end they came from. 

When you get the truck assemblies out, you can test them for binding by inserting a small flat-bladed screw driver in the hollow part that the driveshaft end goes into.  By turning the screwdriver with your fingers, you can check for binding.

Certain older Bachmann locomotives used a white plastic gear on the axle shafts.  These gears had a tendency to split in use.  They will crack parallel to the axle.  They will not fall off the shaft, but the crack will result in there being out-of-round.  This destroys their ability to rotate in mesh with the idler gear in the truck.  Again, the chance of this happening to two different locomotives is slim.

Finally, when re-assembling the loco. the brass hoops at the top of the pickup wipers have to be below the halves of the frame, not between them.  The electrical contact is made with the underside of the frame.

Les

[railtwister]

If the DCC circuit board doesn't make good contact with the little phosphor bronze fingers that provide power to the motor, the lights can come on but the loco won't move. This is especially common in N scale, and usually requires removing the decoder board and tweaking the fingers so that they make contact with the appropriate part of the decoder when it is re-installed. There are other things that can cause your problem, but the above is the easiest and cheapest scenario.

Good Luck,
Bill in FtL

[seadowns]

Well,
I cured this problem with some small peaces of foam glued under the fingers on the board in order to provide more pressure to these fingers,
and this worked flawlessly since!

Regards
Mathi