I'm starting to build a new layout (after 19 years out of the hobby), using major sections of my old layout. Some of my turnouts are Atlas SnapTrack and some are Peco and others with "hot frogs" that change polarity when the points are thrown. I understand that this can be a problem with DCC. Do I have to replace all my hot frog turnouts, or can I either modify them, or ???? Extensive replacement would probably mitigate against converting to DCC! Any suggestions would be appreciated. Also, how are reverse loops and crossovers handled in DCC?
The problem with hot frogs is that a locomotive approaching from the trailing (frog) end, on the route that the switch points are set against, can overrun the gap that isolates the frog. That WILL cause a short, the breaker WILL open and the entire power district (or the entire layout) will come to a sudden stop!
That said, it isn't that difficult to install signals on the layout and/or indicators on the control panel to indicate switch position. Then it's just a matter of the engineer(s) paying attention to what's going on - the old, "Hand on the throttle, eyes on the rail," bit.
It's also possible to isolate a short length of rail (long enough to stop your longest locomotive) on each track on the trailing end of the frog, and connect it through contacts on the switch machine so that it only receives power when the points are properly thrown. The train may crash-stop, but it won't put the entire railroad off-line.
All of my hand-laid frogs are 'hot,' because I have some rolling stock with extremely short pickup wheelbases that can't span an insulated frog. I use the stop sections I just described to keep trains from overrunning the clearance points.
(Chuck (Modeling Central Japan in September, 1964)
Personally. I prefer "hot" frogs. They reduce stalling through turnouts That's especially good when running sound decoders as a stall will cause them to restart each time they lose power on a frog.
Remember that a short circuit is a short circuit. If it shorts on DCC it was shorting on DC. You just didn't notice it because most DC equipment's short circuit protection is slower than DCC short protection.
Martin Myers
Welcome
Here are a couple links to great sites that have the most valuable information od DCC any one can use. There are a lot more but these are great and do not tend to scare new people to DCC.
http://www.wiringfordcc.com/switches.htm
http://www.members.optusnet.com.au/nswmn2/DCC.htm
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!