Last month a friend purchased a pair of PRR Key E8's at the Chicago show for me. Yesterday I completed the DCC installation and thought I'd share pictures and info about the upgrades. For recent diesel installations I've been using a mix of Soundtraxx Tsunami2's decoders. TSU4400 4 amp decoders for higher current draw units and TSU2200 2 amp decoders for lower current draw ones (eg: Atlas single motor switchers). For the Key E8's I went with TSU4400's along with Soundtraxx's Current keepers for improved performance on dirty track. For speakers I used 1.7" QSI Hi-Base speakers left over from a prior project. Before installing the decoders in the locomotives I ran them on a decoder test stand I made years ago. It has a motor, speaker, and provision for testing various lamps, LEDs, and resister combinations.
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I've found it handy to use a NCE PowerCab on the workbench - both for initial decoder testing and later for setting CV's while the model is running on a roller stand. (After a year or so I sent the PowerCab to NCE for radio upgrade. During operating sessions it serves on the railroad just like other NCE wireless cabs).
After bench testing of diesels in DC mode I was disappointed with the look of the factory installed lighting - the headlights a were too dim and the cab and number board lights were too bright. I decided to replace the original 1.5v incandescent bulbs with warm white LEDs. 3mm LED's were used for headlights and very small surface mount LED's were used for the number board and cab interior lights. The 3mm LED was a direct fit in the Key headlight reflector. I shouldered the surface mount LEDs with several layers of heat shrink tubing and a fiber washer to adapt them to the existing number board housings. Each LED was wired in series with a 1k ohm resistor. I reused the existing Key printed circuit to mount resisters and make a connection to a 7 pin plug - 5 wires for lighting, 2 wires for the speaker. LED lighting intensity was customized to each function using decoder CV settings. (The TSU4400 has 6 separately controllable lighting ports). The photo below shows the TSU4400 and Current Keeper mounted on the locomotive chassis using double sided foam tape. With the chassis unplugged from the body I was able to run the chassis on the test track and out on the railroad to check for issues. With the chassis on the test track and plugged to the body in the foam cradle I checked the lighting and sound connections. To facilitate assembly and maintenance as a general practice I use one or more small jacks to connect boilers/bodies with mechanisms/chassis. Color coded wires and heat shrink tubing help keep things straight.
The second photo better shows the raised perf board shelf for mounting the speaker in way that it is under the fan openings while clearing the drive train tower.
After several test runs on the layout I was disappointed with the electrical pickup. On this relatively early run of Key E units pickup wipers were used on only 2 non insulated wheels of each truck. Back to the workbench. In somewhat short order I added phosphor bronze pickup wipers to the insulated side of each truck using a small piece of printed circuit board and the existing Key side frame mounting screws.
The units now look, run, and sound very nice pulling the Broadway Limited (note the ATSF transcontinental sleeper).
5670 and 5671 were the lead units in the last order of 12 EMD E8's delivered to the PRR in October 1952. That order introduced a new standard painting and lettering arrangement for PRR Passenger diesels - 5 stripe synthetic buff (dulux) on Tuscan red bodies. Prior E7's and E8's were painted Dark Green Locomotive Enamel (DGLE) with gold stripes and lettering. As delivered the stripes ran across the side port hole windows and the nose keystone carried the engine number. A year later the standard was again revised removing porthole stripes and replacing the locomotive numbers on the nose keystone with overlapping PRR letters. Key painted and lettered the models in the as delivered scheme.
