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EMD 7707 overview and DCC install

Last update: November 13, 2016
(click on the pictures to see larger picture, redirect to flickr)


Brief history of the EMD 7707

It was built in 1953 at the GMD plant in London Ontario, with a 12-567B engine. It was rebuilt with an early 567C at EMD plant at La Grange in Illinois. It was shipped to Europe and received by NOHAB (Nydqvist & Holm AB) in Sweden. It made EMD demo tours throughout Europe which resulted in various NOHAB and/or EMD orders. In 1956 the Swedish Railways (SJ) bought the locomotive and renumbered it to T5.205. Later it was renumbered to T42.205. In 1966 the locomotive had a major revision and lost its dynamic brakes (there were put out of service years before) and it also lost the EMD demo colors as it was repainted in SJ colors. The former 7707 ran mostly in the far north of Sweden and typically as a B unit, paired with another SJ locomotive (typically a T44). In 1983 the SJ retired the locomotive and it was bought by a Norwegian group (GM-Gruppen) that was into preservation of GM/EMD locomotives. It arrived in Norway in 1986 and was restored to service in the EMD demo colors. Upon the demise of the GM-Gruppen it was sold to the Swedish railways museum where it is resides today (in operating condition).

EMD factory picture - G12 No. 7707

D09520 - G12 7707

EMD 7707 in HO

NMJ made a small brass series of the SJ T42 and the EMD 7707. The model was produced by Ajin in Korea. It has all the typical elements of a brass locomotive and it has some nice details. As it was made before DCC became main-stream it has no provisions for easy decoder installation. In this article I describe how I installed a DCC sound decoder.

NMJ G12 7707

NMJ EMD 7707 sound install The three items needed for this project:
  • NMJ EMD 7707
  • ESU LokSound V4 DCC decoder
  • ESU 50321 sugar cube speaker
I used the ESU Full Throttle 12-567C sound project. This project has the same EMD engine as the G12.

NMJ EMD 7707 sound install

Prior to installing the decoder I have removed the trucks and cleaned the gears and wheels to ensure proper running. I did a quick test on DC and it ran great. The LokSound decoder is installed on top of the motor using double sided tape. I removed the original light board. The lights are hooked up using resistors that I wrapped in shrink wrap (yellow and white).

The speaker housing was put together and you can see the small speaker in the top of the picture.


NMJ EMD 7707 sound install The speaker is installed with double sided tape in the small space at the end of the long hood. The wiring is taped together using kapton tape.

EMD 7707, NSB Di3.602 Arrived at the Dombås layout, together with the NSB Di3.602.

The video demostrates the sound functions of the EMD 7707 and also the NSB Di3.602 which I built based on a Heljan model.


Copyright 2016 Lolke Bijlsma