Fas-track Siding Track power

[lionelsoni]

The Kw is typical of postwar Lionel "Multicontrol" transformers. There are two rollers on the main 14-volt secondary winding, which is in series with the circuit breaker and the 6-volt secondary winding, which then connects to the common terminal, "U". You can easily see that any current flowing between the "A" and "U" terminals passes through the circuit breaker and that a fault between those terminals will trip the breaker. Likewise for the "B" and "U" terminal combination.

However, any current flowing between the "A" and "B" terminals passes only through some part of the 14-volt winding and not at all through the circuit breaker nor the "U" terminal. Unless the "A" and "B" controls are set to the exact same position on the winding, there will be a voltage between them; and connecting them together will cause a fault current to flow, which can be quite large. Nevertheless, the circuit breaker will not trip. Instead, the wiring or the transformer winding or both will burn up.

Your statement that you intend to connect the transformer common to the center rail is particularly troubling. It is normally connected to the outside rails, with a gap in the center rail between blocks. If you do it the other way around, the short circuit that happens when the train passes the gap will last much longer, with current flowing from one car to another through the couplers. (Current flowing through a coupler will often burn out the knuckle spring for good measure.) With the usual connection, the short circuit, however harmful, at least happens quickly (unless a locomotive or lighted car with double pickups stalls right over the gap).

I noticed that, in the Lionel service manual for the KW, there is actually the warning, "Note that the circuit breaker does not protect binding post combinations A-B, B-D, and C-U."

[yelliss]

WAS reading the responses to this siding track problem and generally am in agreement with it. However the last paragraph of Bob's i don't understand as it seem to me that this would be the perfest set up and is what I Inten to do with my KW 190 AS IT HAS A CONCURENT 'GROUND" for both a and b th
rotles.this common ground I intend to hook up to the center rail. "no ?" very confused Ellis[?]

[lionelsoni]

You have to have a gap in the center rail in any case.

You are right to observe that there will be a "conflict between the two transformers when the engine passes the block". Unless the track on both sides is powered with the same voltage and the same waveform, there will be a fault current as the gap is bridged, and very likely an inductive voltage spike when the fault current is abruptly interrupted by the pickups' moving off the gap.

Even having the same voltage and phase will not fix things if the two transformers produce different waveforms, as modern "transformers" often do. But, using two outputs from the same transformer is even more dangerous, since Lionel usually put in only a single circuit breaker, which does not protect against fault currents flowing between two of the transformer outputs.

[Anonymous]

If i use two different power supplies one for the main line & one for the siding track do i still remove the center rail wire on the block section.? And will this cause conflict bettwen the two transformers when the engine passes the block. Everyone has been a big help & i thank you for that . Im new to the hobby And i rather ask than cause a disaster.

[Anonymous]

Sure can. It doesent matter how you turn the power on and off, be it a toggle switch or the other side of your two handle transformer.

[Anonymous]

I have one more question. instead of a switch can i use a seperate power supply. I use a mrc pure power duel Transformer using only one side. Can i use the other side for the Siding Track with a block section? Thanks for the answers guys .

[Chris F]

Here's what Mark is talking about:
http://www.lionel.com/products/productnavigator/InstructionManuals/71-2060-250.pdf
If you're using one transformer, you'd cut the wire shown in Figure 2 (the one to the center rail), then connect the ends to an On-Off (a.k.a., single-pole, single-throw or SPST switch) to control power to the siding.

SPST switches are available at Radio Shack, Lowes, Home Depot, etc. I recommend one rated to handle at least 10 amps. You won't need that capacity now, but you never know where this hobby will lead!

BTW, [#welcome]

[crip]

You can use lionel fastrack block sections and a atlas slide switch.

Mark

[Anonymous]

Hi. Im new to model railroading. I use lionel fas-track i have two train sets . I run one while the other stays on a Siding Track. I would like to make a switch to shut the Siding Track on and off with some kind of toggle switch for the times i want to run just one set. How can i do this? This is for the Lionel Conventional Control engines..