OK, I think the Atlas switches have been the problem all along. When the Blue Comet, ( MTH 263E) passes any of the switches unless at a high speed, the engine shuts down, or if being run in off mode, it stops, then starts up the engine sounds. It will NOT run at this point however, but can be turned off or on as many times as you wish. I checked the Atlas switch for electric and there is one little rail on the neg or neutral rail that does not have continuity, but none of the Atlas switches installed ( 15 of them ) have continuity on that little piece of rail. It appears to float or be disconnected from all other parts of the switch. However, the rail OPPOSITE that little piece is connected and will provide a complete circuit. So…any ideas on this one? Thanks much, Jake
PS. The Blue Comet has always had problems with these switches and my Post War 1666 will run across the, but sometimes it sends it into neutral mode, or uncouples the tender.
Take a look closely at the neutral (common rail) from bottom of switch and I think you will find that all outside rails are connected. there have been a number of cases where these are very loose. A drop of solder should clear that up.
If your switches were purchased prior to 2000? then the wire is embeded in track. Otherwise there are small wires connecting the rails. Generally speaking the problem with these wires is that they are way too small for running at greater then about 4-5 amps. They can get very hot and in the extreme situation of derailment will actually heat up and melt if there are no fast acting circuit breakers (older transformers).
the problem is usually with the center rail.
the connections of these wires is often loose and-or as above could have overheated.
In particular at the head of the switch the center rail has cut in it and is connected with small wire, this wire is usually first to go. If this wire goes then a dead spot on center of switch occurs. When you go fast there is enough momentum to carry, At slow speeds, especially if wire is hot , not enough power feeds the engine. Conitunity tests will come up positive , but you still have a bad connection.
The Atlas switches are preped as follows. The center rail space at head is filled with copper foil, the sides are burnished and conducive paint is applied to the side and top of rail at this point.
The other center rail wires are cut, so that the atlas switch is the end of a power block. Each switch has effectively three feeds.
hope this is helpful