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Front Wheels Jump Track
Timothy asks readers:
“I have several HO engines that the front wheels jump the track, even on straight sections. They act like there is a spring missing that may hold wheels to the track. I don’t see where there is any place to put them (springs). Not just one brand either.”
13 Responses to Front Wheels Jump Track
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I’ve had several Bachmann engines that have done that. What I have learned is the screw that holds the truck on gets too tight in the truck can’t freely wiggle and move with the track. Make sure that your pieces that hold the truck to the frame aren’t too tight. That could be a good source of the problem.
Dave I have an “O” gauge Bachmann engine that jumps the track when I use a switch. I tried your suggestion and backed the screw off the front truck thanks for the tip.
No problem bud!
I had that problem with an MTH steam loco. The wheels on the front truck were out of gauge. The NMRA has a standards gauge which allows you to check wheels, track and couplers for correct distance, width, height. If you don’t have the gauge, put your loco on the tracks, run it at slow speed and look at the front truck. Make sure the flanges of the wheels are on the inside of the track. If it is occurring on a specific section of track or on a switch check the track for looseness or possibly a bend in the track. If it occurs on a switch, check the frog height and guard rail. Improper height will cause a derailment.
Have you checked that the wheelsets are in gauge? If you can, also remove the wheelset and check that the wheels are actually perpendicular to the axle. Misalignment can result in the pilot wheels running crooked and being prone to derailing. There is not a lot of load on the pilot wheels, so they might be very sensitive to any alignment defect. If they are crooked, careful bending may take care of the problem.
I had a problem with a Spectrum N scale recently on a 2-6-6-2 and had to make new wheels as the flanges were too small in diameter. The same happened to me earlier on a Rivarossi N scale 4-6-6-4 and it was the spring was captured in between the frame and the front truck and as soon as I loosened the truck mounting screw it popped out. After that it ran fine. A lot of manufacturers only run their products on a straight section of track and things like this get missed. Good luck and happy HO ing.
I had a 4 6 0 HO steam loco that had problems with the front truck I put a small amount of extra weight on the truck frame and this fixed the problem. I had loosened the screw holding the truck in place as well. I hope this helps.
First thing to check is the gauge of the track. I will bet you will find that in the areas where the pilot truck jumps the track gauge is too narrow. this is often caused by the track nails holding the track in place have been driven in too far. This will cause the ties to bow and slightly pull the rails closer together. This is not an uncommon problem with both experienced and novice model railroaders. I hope this helps.
I think you should also check to ensure the back-to-back gauge of the wheels are correct. That can also be a reason why wheels jump the track.
As it is happening with several locomotives check the track, particularly where you have joins on set track and where you have bent flexitrack. Some locomotives will be more tolerant than others of track alignment and this may be dependent on the size and wheel configuration as well as the make.
Not so relevant here but connected I had a problem with an 0-6-0 tank locomotive that would derail then re-rail itself on an S-bend. It was happening in the middle of a piece of set-track and only that locomotIve was affected. I eventually worked out it was the passenger coach coupled to it that was pulling it off the track on the curve. The moral is don’t rule out an issue with something other than the locomotive, even if only one is affected.. . .
Thanks guys I found something wrong with each engine 2 needed screw loosen one I add weight
the rest flanges were tight
Thanks again
Tim
Your trucks need enough play so the wheel sets can flex from front and rear of each truck and also from left and right. The gauge of the wheels can play the problem as several of you have said. Some cars don’t have a very good bolster that holds the car up enough to clear the underframe from the wheelsets or truck parts. I have found that on a few engines and several cars I have purchased used All fixable. Also watch for protruding parts of the truck as the truck turns make sure it clears everything. I have an engine doing that now and a little bobble in the track making the truck flex up and down from front to rear will cause the truck to catch and not return in its travel ( Maybe a bad casting of the frame catches as the wheel set flexes as said above. Yep Agree with what has been already stated. from Newman Atkinson
Hi guys ref the pony truck screw …. if you do have to loosen it (or if it keeps coming loose) add a tiny drop of ‘Locktite’ or other brand of thread glue. It can be pricey but it’s worth it. I’ve even used it on old Tri-ang running gear when the tiny screws holding it to the wheels came loose… never had the problem again.
Ian