A friend of mine just picked up two new Atlas Dash8-40CW units. One was the Santa Fe red and silver warbonnet and the other was a CSX in the blue and yellow scheme.
He has Peco switches and these units were continually shorting out on them. He returned both units to the store where he got them and the owner got out a micrometer to check the wheels. He said that the wheel tread itself is wider than on earlier units and that the flange is thinner. He said that the combination of the two was probably enough to cause the problem. It allows the wheeel to drift over enough that it shorts acroos the rails at the frog.
Has anyone else had this problem or heard anthing about it?
Wheels are gauged at the flange. If they are in spec, there shouldn’t be any problem with the loco. Variations in tread/ flange width shouldn’t have any affect. NMRA standards gauge will give the max and min for gauge, why would someone use a micrometer instead.
Bob K.
You’d use a micometer to determine whether or not the wheels and flanges varied in their dimensions from those of earlier production units and by how much. The NMRA gauge is fine as a simple check to determine that things fall within a given tolerance, but it’s not a tool that you’d use to get an exact measurement.
In this case, they were able to determine that the flanges were .004" narrower than earlier units and that the wheel treads were .004" wider. The combination means that the wheels are able to move farther to one side or the other. On switches, this makes it more likely that the wheel treads are able to bridge both rails at the frog and cause a short.
He has quite a few locommotives from Athearn, BLI and Kato and they don’t have this problem. His earlier Atlas units don’t have this problem either. Common sense would suggest that since these two units are the only ones exhibiting this problem and that they also have measureably different sizes of flanges and wheel treads, there must be a connection.
You won’t get that information from an NMRA gauge.
Glen1, I had the same problem with peco non electric frog switches. Every time my Kato dash nines would cross the switch they would short out. I finally had to gap the rails as if the switches had live frogs. This worked and five years later I’ve never had this problem again.
One of the things about Peco switches, except for the new Code 83, is that Peco uses Euro Standards and they are slightly different than our standards. If you check, you will find Peco code 83’s are made exactly like they should be.
Most all of our products can run on the EURO Peco difference, but some do have problems with Peco.
The new Atlas might be just at the edge of having this problem.