Just brought home another train show “find”. It goes in reverse ok, but in forward the rear drivers freeze up while the front drivers are still ok to try & turn. Anyone have any ideas? Also, how do you tell the age (model year) of AHM/ Rivarossi stuff? Thanks in advance.
AHM (Associated Hobby Manufacturers) has been out of business for 20 years or more, and was last known as IHC (International Hobby Corporation), both owned by the same person, so that might give you an idea of its age.
I have a few old Rivarossi (AHM) steam locomotives. My 2-8-8-2 did not have that problem, but the SP Cab Forward did. … The cylinders are molded in the frame, and there was a break in the frame where it meets the cylinder block. I was able to super glue the broken part, and that was all I needed to do. … Try to wiggle the cylinders while holding the frame. Be careful not to bend the drive rods while doing that. . If the cylinder block is loose, you will probably be able to see where the frame is broken. Now you should be able to super glue it back together while making sure the piston rods are in the holes of the cylinder. … That should correct the problem of a broken frame if that is the case with your locomotive…
I might inspect the clearance on the worms and worm gears. If it runs in one direction and won’t in the other direction, perhaps the worm is climbing up and comomg out of mesh with the worm gear. Also look at end play in the motor. Going one way pulls the armature toward one end of the motor, going the other way pushes the armature to the other end of the motor.
Before taking anything apart, take some notes and some photos to help you get it back together.
You might try to remove the boiler and cab and run it where you can see the drive shafts, gear boxes and other moving parts. I have done this with my Big Boy and found the open drive will reveal problems most of the time. Also, check the drive rods as sometimes the hex screw works loose and it may bind in one direction and not the other.
-Bob
If you decide to dissasemble the drive wheels note that the front and rear axle in each set is different then the middle two to allow it to track on curves. Took me twenty years to discovet that.
If you can find, perhaps at another swap meet, an old AHM parts catalog, they showed the different vintages of various locomotives and that might help you date when yours is from. At some point they slightly reduced the absurd size of the flanges (but did not increase the size of the drivers, which were undersized on the AHM/Rivarossi steamers). A surprising number of changes took place on some of their engines.
There were also some aftermarket drivers offered for that locomotive, as well as an aftermarket regearing from NWSL if memory serves. Somewhere I may have those gears in a package.
My own 2-8-8-2 was one of the first offered from the mid 1960s, and my folks probably bought it for $35. It was a memorable Christmas present. At that time the detail level was considered to be extraordinary and it remains a good looking model. It was also considered to have an unusually quiet and smooth drive for the time – meaning it did not grind. As with most steam locomotives I am always reluctant to suggest taking the mechanism apart if you can get it working the way you want.
Dave Nelson
Check the exploded drawings on HOSeeker. There are drawings under the 2-8-8-2 listing and the Scratch Builder’s Bible.
http://www.hoseeker.org/ahminstructions.html
The 60’s version had engine and tender pickup, but in the 70’s that was changed to loco pickup only.
I would check first for binding rods / valve gear or a loose axle cover, and also check the helical axle gearing. It’s all brass and can wear out if it wasn’t kept greased.
If you go in & black out a lot of the brightwork & weather them a little, they look great. I can’t afford the new stuff. These are nice if they run.