Lionel H-12-44 Switcher worm gear help needed

You might try contacting Dave&Lynda at Northwest Shortline, 'the gear people'.   You'll need to give Dave some gear info to work with...number of teeth, OD of the gear, bore diameter, face width, spur gear or worm gear (straight or angled teeth), etc..  They might be able to help....especially where manufacturers have 'walked away' from providing replacement parts.  

You might also contact Brasseur's in Saginaw, MI, with the Lionel p/n.  They might have it (their website is fairly up-to-date....I'll let you do the checking.)

Just a couple suggestions....others may have additional.

Then, there's always York....

FWIW, always...

KD

An h-12-44 is Not a "baby trainmaster" it's a switcher. A baby trainmaster looks like a trainmaster except it's a few feet shorter than a regular trainmaster the only surviving example was working for T.V.M.

Lionel’s H-12-44 locomotive, one of my favorites. For those who do not know, the H-12-44 was designed around the same time as the Veranda turbine. Like the Veranda, it is completely cast metal in construction and is very heavy for a locomotive of its size. It has both magne-traction and traction tires and is propelled by a universal motor (“Pullmor”). The H-12-44 will easily pull 40 scale freight cars on flat track given its heft and traction tires. But there lies the problem. Just because one can pull a huge load does not mean that one should pull a huge load. Huge loads can cause gears to be stripped. Gears that are now no longer available.

Unfortunately the H-12-44 was produced just once in three road names. Parts for the locomotive can be difficult to come by. If the correct worm wheel is not obtainable, there is hope. The H-12-44 is based upon the postwar NW-2 and the motor is similar between the two. What will need to be done is convert the current motor to the 623-100M motor used in postwar NW-2’s and GG-1’s.

The armature in the H-12-44 is its own unique design. The main armature shaft is much thicker (almost ¼ inch) than the usual 3/16 armature shaft found in universal motors. The worm on the shaft is double cut rather than the usual triple cut. Thus a drop in replacement is not possible. However you can convert the unit to accept a 623 motor if you cannot find a correct worm wheel.

A wheel will need to be pulled, but that has to happen anyways. Instead of the part# 610-8848-022 worm wheel, the 623-22 brass, or 623-22D delrin will be used and pressed onto the magne-traction axle. The motor will need to be modified. The 8848 armature will need to be removed and the bronze bushing knocked out of the cast metal housing. A 622-109 armature and 622-216 (I think) bearing will be used instead as well as 671M-23 thrust washers (at least 4) and 681-121 thrust bearing (2 of them).

Rather than rebuild the motor to 623 specs, one could simply replace with a 623-100 motor (or modern equivalent) once the 623-22 worm wheel is installed on the magne-traction axle.

Lastly, limit the trains to 15-20 cars on flat track and 10 cars going uphill. That way stripped gears can be mitigated.

I hope that you are able to find the correct worm wheel, if not hopefully this helps. 

WBC is correct, however IMO it would be a real shame to substitute the triple-cut gears from a postwar 623 switcher.  You'll lose a lot of slow-speed performance AND the motor will run hotter at lower RPMs.  If you can't locate an OEM replacement gear, then a custom-made worm and worm wheel with the original gear ratio is the way to go.

WBC - Thank you for taking the time to provide the in depth description and explanation. I'm not holding out much hope of finding one of these gears. I talked with Chuck Sartor earlier this week. After doing some research (thanks Chuck!) he's not sure that this gear was ever offered as a replacement part. Hard to believe that Lionel, with their history of re-using parts, chose to reinvent the wheel for this one-off locomotive.

I'm leaning toward trying to clean up some of the teeth in the damaged area to prevent the lock-up problem as there are a couple of small pieces of plastic gear material hanging that could be getting caught in the gear mesh. Worth a try I suppose. 

If that doesn't work I'll have to consider the 623 conversion route.

I had two of these in the past, one of them had stripped those plastic gears. These are really nice pieces, too bad they didn't use metal gears on these due to the weight of these engines. I do believe I ended up replacing it with a postwar style truck that I purchased on Ebay. My other H12-44 had sound issues shortly after its initial running period. I tried reprogramming the unit, no help. These new fangled electronic engines have been a disappointment for me as I'm now back to all postwar.

Thanks to Rich for his help and all who have replied.  This engine belongs to me and has seen very little run time, probably between 15 & 30 minutes and pushing one or two cars at most. It was switching postwar culvert cars when it just locked up when I tried to reverse it.  I am hopeful we can fix it because I am quite fond of it.

Thanks to all,

Tom