I just repaired, lubed up an old Mantua Switcher from the 60s. Runs fantastic in reverse but runs very poorly going forward. Are there any rules of thumb on what could cause this behavior? Brushes? Gears? I cleaned up the rotor and the brushes and the motor runs pretty well for being 40 some years old. Hoping there is something that can be done here. TIA!
How is it running poorly? Is it wobbling, surging, grinding, etc.? One possible thing I can think of is the gear mesh. Poorly meshed gears can sometimes work pretty well in one direction, but not the other.
Sometimes it runs at perhaps 1/2 the speed it does in reverse for the same power supply voltage. Other times it might move 1/4 wheel revolution and then just stop. You can hear the hum of the motor still being powered even though the engine isn’t moving. Giving it a little push by hand does not motivate it to move either.
When I first tried running it after cleaning/lubing it up it wouldn’t move at all forward. I ran it in reverse for awhile and that is when it would eventually at least move forward, albeit at half speed. And then even you could reverse, go forward and then it would hardly move at all forward.
Surging might be a good way to describe how it moves in forward. In reverse it appears to run pretty smoothly.
Any tips on how to ensure the gears mesh properly? The gears themselves appear to be in good shape.
Ckeck the end play in the motor shaft. If the shaft moves front to back it can change the mesh of the gears due to the angle of the motor in relation to the frame. You may be able to add shims to deduce the end play.
I think I have heard over the years that the running smoother in reverse is common, although noone has explained why that should be. I assume the gearing is the culprit, if this is true. I’d love to find a fix, I have a brass pacific that’s useless as is since I have no need to run my passenger trains in reverse.
Mike
When you say “repaired”, is it safe to assume you placed the bare engine chassis on the track, without motor, and ran it back and forth under finger power to check for running gear binds? On high mileage steamers, wear could cause some pretty nasty effects, especially if the rods got mixed up left to right during the reassembly. As far as the motor, while it’s out for the running gear check, you could hook it up to a couple of leads to a power pack and check for smooth running in both directions. I’ve found worn brushes can cause unequal rpm on direction change. Also, are the drivers quartered?
Lou
Are we speaking of one of their steam switchers? I had the situation of removing the motor (and thus the worm gear) from an 0-6-0T to do some filing and alteration on the frame, and when I put it back together again it did not run as well as it had before, and ran better in one direction than in another. I found I needed to play around a little with the “seating” of the motor on the frame, including the old trick of mounting the motor so there is a piece of paper between the main gear and the worm gear and then carefully removing that paper to leave the thinnest of gaps. I gather the cause was that reversing the motor slightly changes the motor armature’s location. Perhaps a thrust washer would also address the issue but I found I could resolve it by carefully changing the motor mounting – unscrew and screw in again until it runs the way you want.
I had the same basic experience with my old Mantua 4-6-2 and 0-4-0T kits.
Dave Nelson
Sometimes as mentioned it’s just a matter of getting the right tension and play (for lack of better words) between the gears. Try loosening the screws holding the motor in place slightly and see if it runs better. If so, you may as suggested need a shim to allow a little more play in the gears.
I believe the issue is with the motor. I removed it from the housing and then watched it turn in forward and reverse at slow speeds. In reverse it winds up well to the correct rpms quickly. In forward it kind of jerks for a second or two before it winds up to full rpm. So probably a torque issue. The question is, is there any way to fix this on the existing motor?
If not, does it make sense to turn the wheels around so that reverse is now forward?
If you do not want to re-motor, buy some thin flat washers from NWSL and with a small pair of wire cutters or Xacto knife, cut the washer on one side and slip over the driver or gear shat to reduce end play one the shaft. I have done that in the past.
For the Mantua, go to the below site for info. He handles a lot of Mantua.
http://yardbirdtrains.com/index.htm
NWSL has a lot of good info on re-motoring and re-gearing locos and he has tutorials on the subjects.
I bought a catalog that included the tutorials a few years before the Internet came around. Now you can see and download all the info now.
Rich
Sometimes the answer is the simple one. It was the tender. For some reason moving backwards it made better contact with the rails. I cleaned up the bushings and then added a spring loaded contact to make contact with both sets of axels on the tenders. Runs perfectly now, forwards and backwards.
One caveat: in trying to figure this out I did pull the motor apart one more time and cleaned up the armature and the brushes. The motor did function better after doing so. However, the engine still didn’t run right until I also fixed the tender.
Is your Mantua engine one that has no driver contacts but only tender contacts?
I’ve a Model Power/Mantua 4-6-2 Pacific that is tender only wheel pick-up. Long as the track is clean she pulls like crazy with her metal boiler weighing in at 1b. 2 oz. and tender is 4.4 oz.
Glad you got it running right. [Y]
It has driver and tender contacts. The driver contacts were no problem at all as the engine is all brass construction. It’s an 0-4-0. The tender has a plastic shell on it with a metal base. So it is fairly light and that’s likely the reason for the problems I had. A tweak here and there to the design and she runs like a champ now. [Y]
The old Mantua steam engines (and many other engines of the olden days) had the engine wheels pick up on one side, and the tender pick up only on the other side. Adding extra contacts or sliding shoes etc. does often help a lot.