Going Analog

 Motive power on the Clarinda branch of the PVRR has long been a pair of vintage Life-Like 6 axle SD diesels, one SD7 and one SD9, that are mechanically identical and differ only in their paint.

The problem with running 6 axle diesels on this layout is in negotiating the sharp curves. To put it mildly, the SD's do not appreciate the curves going into the meat packing plant or into the team spur by the freight station, and they are not really fond of the end loops, either. These curves are, by any measures, tight, and in fact the packing plant and team track both have to be switched using another car as a handle because the fixed couplers on the locomotives will not even attempt to line up with the talgo couplers on the cars.

I have been eyeballing a couple of Atlas GP7's in paint schemes matching the SD's (one red, one black), and I finally pulled the trigger on them. They arrived Monday and were quickly put to work.

The N scale locomotive encyclopedia has good things to say about the Atlas GP7/GP9, and I have to say I am in complete agreement. The locos run strongly and pull very well. More importantly they both negotiate the tight curves much easier, although they still use a handle when switching out the packing plant and team tracks due to the same fixed vs talgo coupler issue. Being analog they are both very very fast, requiring only a third of the DC PWM throttle in order to achieve realistic road speeds. Slow speed operation is excellent for both of them, they both start at about the same throttle setting although the black one is faster at the start, and remains so through the mid range. Top speed is about even on both, but when the throttle is chopped back to zero the black loco drifts a little farther. The black one has an older frame as evidenced by the lack of motor contact tabs, so I'm guessing the blackbird is a first-run (1995) model and the redbird is a 2004 version with the "slow speed" motor. Either way, there will certainly be no consisting of these locos as long as they are analog.

The redbird is perfect in every way other than the meteoric top speed. I expect that putting DCC in it will tame the beast very well. I especially liked the black treads on the walkways, the SD redbird has gray. The contrast is very noticeable. It has bright white LEDs for its headlights and they illuminate the number boards excellently. The decoders that replace the number boards for this loco (TCS CN-GP) also have white LEDs so that will be a good fit.

The blackbird had some gray showing through the cab windows, but this was easily and quickly taken care of by removing the cab and touching the shell up with a bit of black paint. The LEDs on this one are yellow, so they don't illuminate the number boards as well as the redbird does. That issue, along with the top speed and speed match, will be easily corrected with a decoder installation.

Unfortunately the black loco started out being troublesome. You can see in the photo by looking at the frame rail stripes how the back porch drops past the shell, the front did the same but it wasn't as noticeable. This made the pilots at each end scrape the tracks, worse at the rear. At first the way I attempted to correct this was to file the bottoms off of the pilots, but after running the loco for a while I had issues with it remaining coupled to its consist and losing power when it went over certain areas of track (my trackwork, sorry to say, is less than stellar) because the rear pilot would contact the track and lift the rear truck off the track. Worse still, when operated in reverse the rear pilot would drag on the tracks and produce the most ear splitting squeal.

I took the shell apart and after fiddling with it a while (bend the porch, compare to straightedge, reassemble the shell, darn it it's bent again, WHY?!?!?!?!?) I realized that the problem was the screws holding the couplers in. The frame rails are a separate piece from the walkways and the couplers attach to the frame rails, the problem is the screws were too long. When assembled the screws hit the bottom of the walkways, bending the frame rails down. Once I discovered this I clipped off the ends of the screws and now the black loco is just as flawless in its operations as the red one.

Decoders have been ordered and will be put in as soon as they arrive, until then I have the choice of running the SD's on DCC or running the GP's on analog. As soon as the locos are chipped the SD's will be retired completely, they may make their way out at train shows occasionally but the old Life-Likes have done their duty very well and have earned their rest.