One of the most critical locomotive types on an operating model railroad is switchers. When I began my quest to backdate my operations to the 1950s, I moved with confidence in my switcher fleet. My 1950s Southern Pacific switchers were well-proven workhorses in their former analog-DC use. The challenge was to update them with decoders.
SP Tiger Stripe switchers ready for service.
A critical initial decision was not to install sound in these heritage locomotives. I was unwilling to sacrifice even a fraction of an ounce of weight to a speaker. That choice led to fairly easy decoder installations. I use Train Control Systems decoders for my non-sound installations. TCS has several decoders ideally suited to switcher installations.
First up were decoders for my heritage Atlas S-2s and an S-4. I call them “heritage” because I detailed, painted and decaled these models long ago, shortly after Atlas first released them to market. These Atlas Alco switchers broke new ground for mass-produced models by having their walkways cast as part of the frame. This made them very heavy compared to contemporary switcher models. That weight, coupled with a very good, reliable drive-line led to excellent switching performance.
Train Control Systems has a replacement motherboard for these models, AS6. One simply removes the shell (start with the cab and then the hood slips off) and then the original motherboard. The new motherboard drops right into place on the weight over the motor with the electrical connections built in. The new motherboard includes LEDs at each end to replace the original headlight bulbs.
Although TCS’s instructions do not mention it, I recall many on-line discussions noting the need to electrically isolate the motor from the frame. I chose to do this—better safe than sorry. Isolation required removing the motor (a single screw from the bottom of the frame). I then used Kapton tape on the bottom of the motor and tapped the motor screw hole for a 2-56 thread. I secured the motor with a Kadee nylon 2-56 screw. TCS does call for Kapton tape isolation on a couple of spots on the motor weight.
Atlas S-2 with original motherboard.
Replacement TCS AS6 motherboard and decoder.
Completed S-2. Note the front-right grab iron ladder—black grabs against the orange stripe background. Note the second grab up from the walkway. This is an elongated grab iron with a center support that I did with a Detail Associates eyebolt.
With the decoder installed and the shell back in place, these old workhorses are ready for a new call to service. It did my heart good to work with these old units. It was a pleasant reminder that once upon a time I was a serious motive power modeler as seen with the grab iron treatment (vs the stock shell cast-on grab irons) and the tiger stripes. Yes, Atlas has since then produced updated versions of these classic switchers, some runs with DCC decoders, but my heritage units still compare well to more recent production.
A note on the switcher fleet make-up. Although Oregon became home to Baldwin switchers by the late 1950s, Alcos were part of the mix in the mid-1950s. Given the weight of my heritage Atlas models, I will stick with them!
The other half of my switcher fleet are, indeed, Baldwins. I have a mix of Stewart models ranging from a VO-1000 through S-10s and S-12s. The VO-1000, S-10, and one S-12 all have conventional single headlights on each end. The easy solution for these units was a TCS DP2 decoder. This is a fast decoder installation. It retains the Stewart LED headlights.
Baldwin S-series switcher decoder installation. The upper unit mother board still has the DC shunting connectors in the eight-pin socket. The lower (front) mother board has a TCS DP2 decoder plugged into the socket.
My final decoder installations were in a pair of S-12s that I added the SP’s unique “washer-dryer” headlight housings to each end. These big boxes on each end of the switcher house a headlight alongside a Mars light. My original use of these models only got the headlights “working” (sort of) by routing fiber optic strands up from the single LED headlight at each end into a “twin sealed beam” conversion plate that I fabricated. Consider the lighting on these units as work in process. I need to replace both my fiber optic headlight attempt and the factory single LEDs for the headlights and then add separate LEDs for the Mars lights. That extra lighting will be supported by my use of TCS A4X decoders. These are replacement motherboards that can support either light bulbs or LEDs for the four supported light functions.
Baldwin S-12 with TCS A4X decoder. This is a replacement motherboard style of decoder.
Baldwin S-12 switcher, SP Class DS-114 with large headlight and Mars light box housings.
It was good to work with my heritage fleet of SP Tiger Stripe switchers. It was a good reminder of where I have been in my modeling and to note there remain some projects that demand a return to basics of detailing, painting and decaling. My Baldwin DS-114 class switchers still need headlight and Mars light work, but that path is a lot clearer today with LEDs and sufficient decoder functions.
