Agreed. For any two DC engines on the same contiguous length of powered track, when one gets applied voltage via the power supply and rotating throttle, the other should get the same voltage. What happens thereafter depends on the nature of each engine. If one is a slow-geared Shay, for example, it will trundle along as that voltage will. The other engine, if it is a high-stepping Pacific meant for passenger service, will probably move off at nearly three times the speed...give or take.
Without some other means of controlling at least one engine, you need blocks or track diversions, or parallel tracks, or switches to cut off power.
With DCC, unless you specify which decoders/addresses to perform any function of any engineered permissible performance, you needn't worry, the engine won't do a darned thing. The resident decoder must read information packets addressed to it specifically, or it won't act. So, it can stay parked while the one engine moves or turns lights on or off, sounds the horn...your call.
Crandell
If they run close to the same speed, you can run them both together, like two engines doubleheading to pull one train. You won't be able to control each engine separately however; to do that you'd have to create separate blocks of track and have two power packs or throttles...or switch to DCC.
caballorr,
As long as the speeds of any two locomotives are the same or nearly the same, you don't need DCC to operate or MU them together. However, if they don't operate at identical speeds, this is where DCC has an advantage over DC because you can then speed match each locomotive for optimal MUing. Obviously, each locomotive would need to be outfitted with a decoder in order to achieve this.
Hope that helps...
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
I have one single track loop that is dc power . I would like to know if you can run 2 locomotives together or do you need to use dcc ? Also can two different brands of locomotives be use together with dc ? Right now I one locomotive made by Life Like. It has been in use now about 11 years It run good but I would like to have two locomotive running together . Thanks in advance
~ Tim .
To see photos of my HO scale / 1/64 scale layout and diorama photos base in the present day . http://www.flickr.com/photos/icr140/