It is stated in frequently asked questions on E-Z Command '
Can I operate my existing non DCC locomotives on my E-Z Command System?
Absolutely. Bachmann E-Z Command® supports the operation of one non decoder locomotive at a time. When button 10 is pressed the speed control and direction buttons control the non decoder equipped locomotive.
Alternatively you can plug the AC power pack into a Bachmann analog throttle and plug the throttle into the E-Z command using the supplied cable into the E-Z Command. When this is done the analog throttle controls the non decoder equipped locomotive and Button 10 controls a digital locomotive with the address of 10
If you do this, are you running a risk of damaging the non-decoder equipped locomotive in order to save a few dollars?
Also would the risk of damage be greater running DCC equipped and non equipped at the same time?
Tom
To answer your first question: the answer is that, generally, any damage done to the motor will be negligible. The exception is that you must not let the locomotive idle on DCC power for an extended period of time. That will almost certainly damage the locomotive. To prevent that, build an electrically isolated siding for your DC locomotive to stay when you're not running it. Or, simply remove it from the layout when your not using it.
As for your second question, I believe not, but I am not entirely sure. Jim Banner or one of our other DCC gurus should be able to answer that question with more certainty.
If you are truly concerned about running DC locomotives on DCC, then you might want to save yourself a little anxiety and install decoders. However, as long as you don't let your locomotives idle, you should be fine running without them.
Timothy
You would be slightly less likely to damage the dc locomotive if you were running DCC locomotives at the same time. This is because track voltage drops a bit when running more locomotives. However, the difference is small and Timothy's advice to park the dc locomotive on a dead track when you are not running it is still applies.
Jim
Thank you for the information it is helpful.
Tom