Custom Painted P-2000 units

Saturday, November 7, 2015

Removing and Replacing a Bachmann F7A Prime Mover

Greetings All,

A few weeks ago train NE-97 was rolling through Empire City when the lead engine, Erie Lackawanna F7A suffered catastrophic engine failure. The engine was shut down and brought into the New York Central Train Layout Terminal Yard Shop for evaluation and possible repair.

The F7A in question is a Bachmann Plus unit bought when they were first released about 15 years ago. This is a straight DC 8 wheel drive dual fly wheel equipped engine. It had been a good rugged engine for it's entire service life until this motor failure. So what to do? A common question among modelers who operate aging fleets. Options include repowering, converting to non powered free rolling "dummy" unit, putting it on a display shelf, putting it back in the box and forgetting about it, etc.

The N.Y.C.T.L. Purchasing Department was contacted and approved the purchase of three new Bachmann motors directly from Bachmann. I believe they had a 20% off coupon burning a hole in their collective pockets. The purchasing agent checked the in stock availability of replacement motors and found F7A motor# 8812A deemed to be the 6172 replacement motor and an actual 6172 motor listed under the H16-44 parts section.   

The original 6172 type was chosen and the parts arrived within a week. Follow along as the N.Y.C.T.L. Shop gets down to business.

Shell and frame are separated. Engineer and Fireman refused to leave their posts.

Shell, frame, gear towers trucks and old motor sit at the N.Y.C.T.L. shop. Note that the old motor has been marked top and with arrows to remind me which way the new motor needs to be orientated. 

The N.Y.C.T.L. shop switcher shoves in a replacement EMD prime mover towards the overhead crane. 

 The model prime mover is from Walthers. A four axle BB U boat watches from the ready track 

The new 6172 motor is on the flat car. Note the plastic couplings protruding from the flywheels. The old 6172 motor had the couplings inside the flywheel. 

The new motor is placed in the frame. The extended plastic couplings needed to be removed for the drive shafts and trucks to fit properly. To do this grasp each flywheel and pull out the extended couplings with a needle nose pliers. To remove the couplings from the old engine for reuse I used a screw as an auger. The point of the screw rests against the drive shaft and the threads back out the coupling nice and neat. 
Also visible here is the 2-56 screw that hold the draw bar for the connection to the F7B.  

The new motor has been installed and all connections soldered. Note the black straws covering the soldered joints. Another use for these black coffee stirrers that I received courtesy of PC Ralph. They are one of those gifts that keep on giving.

Erie Lackawanna F7A-F7B-GP7 lash up ready to return to revenue service. 

That's more like it! The EL consist has this freight well in hand as it crosses the Empire City viaduct.

The EL EMDs encounter a pair of Fairbanks-Morse H16-44s on the upper level of E.C. The H16-44s are Bachmann Spectrum products and are about the same age as the F7s. Purchasing the 6172 motor made sense as I can use them in the 8 FM H16-44s in addition to the dozen or so EMD F units on the roster.  


  1. Very nice. I have some Bachmann Plus F7s of the same 1990s vintage. One thing to point out is that you can find new Bachmann F7s DC only in the $45 range on the web. My Spectrums are GN, nice paint, and I have it in mind to swap out the GN bodies with new vintage chassis -- coupler mount is better on the new ones, and there's an 8 pin DCC socket, a big, big plus.

    But your ELs make me think I'm in Marion!

  2. Thanks for compliments and information John! A few years back I bought a blue box Bachmann PRR F7A to add to a 90's era Bachmann Plus PRR F7A F7B consist. The new Bachmann, item# 63001, was much lighter and the motor was not flywheel equipped. It consisted OK with the older units but those older Plus units weighed a ton and are great pullers. The older coupler mounts (same on the 63001) were a pain and for DCC modelers I can see the advantage of the 8 pin DCC socket.
    Aah to be in Marion in the mid to late 60s and catch these units in all their glory!

  3. Nice job getting the dead unit back in service! I always appreciate descriptive posts from modelers who do motor replacements like this; something I haven't done myself. The step by step photos and how-to will be very helpful to me if I find myself needing to refer a loco to the Kings Port shops! Yet another use for the black straws! "The Engineer and Fireman refused to leave their posts" Love it!

  4. Thanks for the compliments Ralph! This repair / re-motor project came out quite nicely and the engine is running beautifully. The flywheel couplings were a bit tricky but once I figured out a solution it was all downhill from there. Glad to pass on the helpful tips to my fellow modelers. We at the N.Y.C.T.L. have no doubt that the Kings Port Shops are up to these and many other tasks. Remember the N.Y.C.T.L. sent up the Breadbox / Clam Shell Coil Cars for repairs and modifications. The Engineer and Fireman are certainly dedicated employees!