A Closer Look At The Walthers Mainline SD60M

The UP's SD60Ms have long been a favorite of mine, and until recently they were very common in Southern California on hauler trains and manifests. Here's a 2015 shot that shows them in their final state, including heavy tagging:

Interestingly, though, 2456 kept its red frame stripe. Here's the Walthers model, with the only change being weathering on the air intake vents:

The Walthers SD60 and SD60M are easy to convert to DCC, and they benefit from it, because they have only one flywheel to leave room for the speaker. By changing CV 3 and CV 4 to 1, you can improve the loco's momentum. But this time, I also decided to try out the Digitrax PX108-2 Power Xtender, which is a capacitor that allows a decoder to power over dead or dirty track. There's enough space on the chassis to install a Digtrax DH126 on the factory 9-pin plug, and the Power Xtender has a plug that in turn fits into the DH126.

However, the Xtender is a fairly big item, and it was a challenge to find a place for it under the shell. As it turns out, the DC non-sound chassis has an insert that's meant to cover the space for the speaker:

If you unscrew two screws at the top of the insert, you can remove it and find a space for the Xtender:

Here's the Xtender tacked into place with Scotch Magic tape. The decoder itself and the excess wires are also held down with tape to prevent any pinching or dislocation when the shell is installed.

Here is the whole chassis:

And here is an example of how the Xtender works:

I left the headlight on and picked the loco up off the track. As you can see, the headlight stays lit. So far, testing indicates that the capacitor will provide power for varying lengths of time depending on the load. The headlight alone will stay lit for several minutes, but an LED doesn't draw much current. The Xtender will keep the motor running for several seconds, depending on the speed the loco was running at the time the current was turned off. If the loco was running at minimum speed, it will stop within a very short interval. If it is going at medium speed, it will run for a foot or so. I have more testing to do to figure out how best to use this feature.

Regarding details, the Walthers Mainline marque is aimed at the lower-cost-but-acceptable market, equivalent to Bachmann, Athearn Roundhouse, or ScaleTrains Operator. These locos are hard to distinguish from higher-priced ones at the three-foot layout viewing range. The biggest detail discrepancy with this UP unit is that it has a headlight mounted above the cab windows, where the prototype UP units have them on the nose.

I added an Athearn EMD PTC antenna array to the cab roof:

Here's a prototype view of a PTC array:

These have been installed within the past several years and are generally contemporary with yellow sill stripes on UP.