Spectrum 1990s F7 vs Current Bachmann F7

Fellow bloggers Ralph V and John R have done various tweaks on the 1990s Spectrum F7, in particular trying to get around the too-wide coupler spacing between units. I had several Spectrum GN F7s that I installed the Kadee short-distance coupler conversion kits on. Here they are when new, more than 20 years ago:

The Kadee conversions were pretty iffy. On one, the truck sideframe-cover plate casting quickly broke after the material removed following the Kadee instructions proved too much. But ever since Bachmann came out with a very reasonably priced F7 in its standard line, upgraded from the Spectrum version, I thought about taking the GN units and mounting them on a new Bachmann chassis. On one hand, I had added some details to the GN units, but Bachmann didn't reissue the Spectrum GN road name in any case.

I picked up an A unit chassis at a very good price on the web. I then took a good look at the Spectrum chassis -- the photo below shows it with the motor partly pulled out to see what I might need to do to convert it to DCC:

This could be done, but it's a hard wire job that involves fiddling with the cardan shafts to get them back in line after you've had the motor out to rewire the thing. Plus, if you look at the drooping coupler in the lower left, the Kadee conversion is still iffy. I just have a few of the Spectrums, all GN, so I think I'm just going to bite the bullet and replace all the chassis with new ones. Here is the new style chassis:

Dimensionally it's very similar to the Spectrum, and the Spectrum body will fit on it. But the coupler mount is redesigned, and it allows close coupling, plus it's DCC ready. Life is too short to struggle with the Spectrum chassis if I can find new Bachmann DCC ready chassis on line for well under $50.

The spectrum body had two projections on the inside to hold the mounting screws:

The new Bachmann body has four, but the locations match up with the two on the Spectrum body:

I had opened out the front coupler opening on the Spectrum unit to do the Kadee install. Getting the Spectrum body onto the new chassis was a little fiddly, but it went on OK. It is a close slip fit, and I just used two of the mounting screws from the new Bachmann loco.

The rear view shows the close coupler mounting on the stock Bachmann frame: