Search the Community

I took the guts out of an MTH F3 and put them into my bashed E8. When using NWSL trucks, there is no provision for the speedometer readout. I took the sensor and mounted it inside the shell of the NWSL truck with a .053 spacer, for proper clearance. The gear ratio of the MTH F3 truck is 10:1 and the gear ratio of the NWSL truck is 25:1, so you can see, some adjustment had to be made. The number of stripes on the flywheel of the MTH truck, both black and white, was 48, so to obtain the correct MPH readout, the number of stripes had to be reduced to 17.5. I didn't like that number, so I used 20 spaces, 10 white and 10 black. There was one more adjustment. The difference in wheel size from a scale 40 inch wheel to a scale size 36 inch wheel. That difference was 1.14 slower. 1.14 into 48, so the 2.5 times slower wheel speed, plus the difference in diameter comes out to 17.5 spaces, again I didn't like the 17.5, so I used 20, 10 white and 10 black. An odd thing happened when testing the readout of MPH. I forgot to put the striped decal on the flywheel and I still got a reading of MPH. I thought that was magic, but when I took the truck apart, I discovered that the flywheel had lines scored across the flywheel, I suppose chuck jaw marks. The lines were shiny, so the sensor picked them up with, I am sure, erroneous numbers. I then put the decal on and retried it and it appeared to read out correctly. Boy, the 25 to 1 gear ratio sure allows for some slow wheel turning, good for scale like initial movement of the loco. Here are some pics. of what the installation looks like. If you have any questions, please feel free to ask. Bob. This sensor is so sensitive, it would probably pick up a Zebra running from 20 miles away.