Re: Switch machine auxilary contacts
With DCC, there is rarely a need to power route anything more than the frog. This wasn't true in the DC days. By not using the switch machine to power route more than the frog, wiring is simpler and easier to troubleshoot.
If you need to use something other than the Tortoise contacts to route power or whatever, you can definitely use a relay. That's how I control the polarity of the power on my balloon tracks. If you just need one set of additional contacts, Don Vollrath describes how to add a micro switch to a Tortoise. See my website at: http://www.wiringfordcc.com/sw_ctl.htm#a18 for Don's how-to information.
Wiring For DCC