switches

[Anonymous]

Wondering if anyone out there is using dcs, or tmcc, and has it operating with 072 or wider switches, such as #7.5, or #5s?. I have not been able to cure a problem of running engines over these swithces at very low speeds, without the engine sometimes dying, or the lights flickering, I am talking about at about 1, or 2 miles an hour. The track is new, the engine, could be new , and still this will occur, and I am talking on very clean track, with shiny pick up rollers. Just wondering if anyone would be willing to give it a try and see what happens. I will explain later why I am so interested in this problem. I spoke to JIm Barret about this, and I will elaborate on what he said later. Thanks a million Rob

[Big_Boy_4005]

Rob, do the engines in question have rubber tires?

My theory is the tires reduce the ground contact points in some cases down to a single wheel depending on the engine. Remember that there is an insulating pin in any switch with a non derailing feature, so you only have a single ground rail to start with. Add that to the single wheel, and any bounce or disruption of contact with that wheel and the rail and you get a stall. The longer the switch the more likely the problem.

Switches have always been a problem at low speed, even before command control. One major problem with 3 rail track is the rollers have to cross one of the outside rails. This means that the rail either has to have it's polarity changed when the switch is thrown, similar to what is done with powered frogs in 2 rail systems, or just let that segment of rail go dead.

There is another possibility which involves the rollers and the center rail, but given your description of the problem I still suspect ground contact. Again with the longer switches, the low angle of divergance may may cause a center rail gap that exceedes the base of the rollers. Long diesels with roller sets on both trucks are less prone to this, but a steam engine or diesel with a single set of rollers may fail to span the necessary distance.