So, this newbie (not near any hobby shop) ordered online and bought two Lionel remote 027 tubular track switches. Then I found out they use 15 V AC. So far, so good, but the MRC AC transformer I also ordered puts out 18 Volts fixed AC and 0-17.5 variable AC. Will this thing burn out the switch motors immediately? Anyone have a solution if this is, indeed, a problem?
It's not a problem.
The O27 switches operate off track power, which is variable voltage AC. Unless you are operating post- or pre-war locomotives at top speed, you won't be using anywhere near 17 volts on the track. When I'm running modern 3 rail equipment (1970s or later), I set up on the 0-11 volts tap of my 1033 transformer, to avoid having everything go too fast.
Virtually all switch machines use in 3 rail O are the twin solenoid type. These use a
short burst of high current to throw the switch. Extra voltage (anything less than 25 volts) simply makes them throw with more of a snap. This is actually better for the coils if the current is shut off as soon as the switch is thrown.
High voltages are not a problem - except for any indicator lights in the circuit. If you are using consistently high voltages on your switches, put in higher voltage bulbs - 18v bulbs. This will prolong the life of bulbs. Bulbs last longer if used at less than full voltage.
The real issue with O27 switches has always been cars standing on the non-derailing rails with track voltage turned up. This will send current continuously to the coil of the switch machine, and may cause it to overheat and burnout. The O27 switches - at least all post-war ones I am familiar with - did not have cutoff contacts like their more expensive O, Super O, and Fast Tracks brethren.
hope this helps