This guy told you wrong. He's thinking of a receiver mounted trackside to control the power to the track. With the Elite, or other constant voltage power supply wired directly to the track, you can control each loco that has a receiver seperately. I have had up to 4 running at once on my layout, all powered off the Elite. One being an Aristo F-1 AB set pulling a string of lighted heavyweights, so the power consumption was pretty great from that train right there.
The TE trasmitter can control up to 100 locos, 10 on each of 10 frequencies. In practice, NOT changing frequencies is what I do, cause simply changing between locos (not complicated) while keeping an eye on multiple running trains & throwing switches is taxing enough.
Back to power, & other comments above, the Elite puts out 22.5V from the factory, but can be adjusted up with an internal set-screw. I upped mine to 24.5V, cause after losing a volt & half to on-board bridge rectifiers, then another volt thru the TE receievers itself, I found things ran much better with the higher voltage.
Again, I'm ready to part with my Elite since I've moved to battery, so if interested, let me know.