Tuesday, March 17, 2015

Brass South Shore Coach Remotoring Progress

The Nickel Plate Products South Shore modernized coach remotoring project has completed successful initial testing, including integration of a late-generation DCC decoder with 'keep alive' technology.

Adapting the NPP coach for installation of the Stanton drive required some cutting of the main floor and the vestibule floor in the body shell, and installation of a new raised floor section for mounting the drive. The Stanton's profile is 1/8" or so higher than the original NPP power truck. After cutting away enough main floor and vestibule to allow the Stanton to swing, I made a new floor section from 1/16" (.0625") brass strip, and offset it from the main floor using 2-56 screws and nuts and a stack of seven #2 washers. I also drilled new mounting holes in the main floor and and drilled and tapped new mounting holes in the body shell to ensure that the floor attaches securely to the body shell.
Side view of the new raised floor section for the Stanton drive truck. The offset is created by a 2-56 nut and a stack of seven #2 washers. The Stanton drive is in the background.
Bottom view of the main floor showing cut to accommodate truck swing, new body mounting screws holes, and four 2-56 screws.
The remotoring project uses a North West Shortline Stanton drive. During DC-only tests, the Stanton performed fairly well after a break-in of 30 minutes in each direction. The Stanton picks up power on all wheels, but consistently stalled on turnout frogs. One of my next steps is to install pickups on the trailing trucks will get pickups; the materials are enroute.

Meanwhile, I have been seeing increasing references to DCC decoders featuring 'stay alive' or 'keep alive' capabilities. 'Keep Alive' decoders use a capacitor to compensate for interruptions in current caused by dead frogs, dirty track, or otherwise inadequate contact. Several DCC makers are offering variations on this capability. 

In addition to seeing references on the bulletin boards and Yahoo groups, Trevor Marshall mentioned the technology in his blog posts on installing DCC in an S scale doodlebug and then in an Overland S scale RS18. Trevor's motive power features sound, and the Keep Alive decoders also ensure that sound doesn't suffer any 'skips' or unprototypical interuptions.  

Testing ain't pretty: the floor of the model and DCC harness
resplendent in electrical and drafting tape used for temporary
mounting. Once the trailing truck pickups and lights are
installed, I will make permanent splices and neat and
functional harness.
Bernie Kempinski's recent post on the topic discussed how Keep Alive decoders added new enjoyment to his modeling by imparting new reliability on his Civil War-era 4-4-0 steam locos, and removing the tedium and expense of powering frogs either via switch machine/throw contacts or DCC frog juicers.

Keep Alive DCC decoders seemed almost too good to be true, but I wanted to experiment with one for the NPP South Shore coach repowering project. I acquired a Train Control Systems KAT22 decoder for this project and temporarily wired it into the model for a test. Other DCC manufacturers offer comparable DCC decoders. I ensured that my test rig wouldn't short or foul the running gear, and then got it on the track.

The results of my test of the KAT22 decoder in the South Shore car did not disappoint.  The car moved smoothly at low speeds, and straight through dead frogs and patches of dirty track--all without the addition of new pickups on the currently dead trailing truck. Its overall performance on DCC vastly improved on my DC tests, which probably says more about the quality of my DC test controls than anything else.

See for yourself: check out the YouTube video below for the test of the coach under DCC control.

With DCC installation under control, I turned back to cosmetic features of this model. I added styrene mounting pads to the Stanton drive for truck side frames, and mounted new, functional pantographs to the roof. Next steps include fitting pickups to the trailing trucks and working out LED lighting.
Evergreen .060" x .250" strip cut cemented to the Stanton mounting pads with liquid styrene cement. The Stanton case is ABS and thus glue-able.

Functional Model Memories pantographs mounted to the roof with 2mm screws. They sit a little high to my eye and some detailing will be needed for the bases--these pans are intended for a Northeast Corridor prototype that mounted with a bit of standoff from the roof. But better than no pans, or non-functioning pans!
New pans reaching for the sky, just like they're supposed to do.