Alaska Railroad #71 Problem

Make sure your drive shaft is still intact and make sure that both of your axles are all of the way in.

Without seeing the proper Lionel manufacturers stock number, like 25345 for example, it is hard to debug.

New pump and filter replaced....I would check out the injectors to make sure they are not clogged...I have a 94 z 71 and had to rebuild entire throttle body..I know it's a diff yr model but troubleshooting is same direction...also have the fuel pressure regulator checked for any problems

1) Try to loose a little the drive belt, for to avoid a higher tension.

2) LUBE very well the deck belt, must shure is worn, proceed with the instruction manual maintenance.

3) Test the input voltage motor, if there are voltage the motor need repair

4) Test the output voltage board, for input voltage motor, if there are NOT the board is faultyl.
See my personal TIPS for HELP.
Try to RUN THE software calibration for diagnose, and troubleshooting
sincerely. God bless you

did you test the alternator? (it's a free test at most local parts stores).
Best regards,
Ck

I'm assuming the train is track powered with a power pack, and not battery powered, so there's actually a few possible solutions. I'll work from the easiest/cheapest, to the more advanced/expensive.

First, especially if the track is old or been in storage a while, the track may have a thin film of dirt, oil, or rust that is insulating the wheels from picking up the power they need from the track. Try cleaning the track with a mild soap but BE SURE TO DRY IT COMPLETELY before reattaching the power. Also, clean the wheels but use a cotton swab and very little water. One drop inside the motor might destroy it from the inside. You can also try a special track cleaning solution sold at your local hobby shop that has HO model train sets. That will work better, especially on lightly rusted parts. Also, make sure all the track connections are tight and free from contaminants.

Then, if you're feeling brave, you can check the motor of the train itself. Disassemble the locomotive and find the motor inside the housing. Check the wires leading from the wheel area to the motor for any corrosion, or loose/broken wires. If it's not the wires which are easy to solder back in place, I wouldn't recommend going any deeper into the motor as it's better and less frustrating to just buy a whole new set.

Finally, the problem may lay in the power pack (inverter) itself. I personally don't bother trying to fix a power pack, but if you know your electronics you could run some tests of the output voltage to the track, and the voltage on the track at various points. Again, it's not worth the time or effort to mess with the power pack unless you know what you're doing. You could get seriously injured or killed by the voltage/amperage running through those things. They even have enough stored electricity after they're unplugged to cause some nasty electrical burns from the capacitors.

Hope this helps and you're able to fix the problem so you can get back to enjoying the train set. I've always enjoyed watching them for hours, especially when I set up my track around the Christmas tree every year! Good luck!

wheels are stuck and the gear drive is jumping over the gears

Check for a fuel shutoff switch, they are made to go off in accidents and shut off your fuel and needs the button pushed to reset

It's something in your steering components or you tires. I've seen both. If your tires are pretty good, it could be your steering stablizer. It's like a shock asorber for you steering system. There also maybe some components wearing out in your steering system too though casuing the stablizer to wear out or unable to to asorb the shock from the bump.