UP doesn't use repeaters on the road channels in the Chicago area, although some of the yards do. Without a picture it's hard to tell what you're looking at, but it's possible you're talking about the folded dipoles that PTC uses. They're at virtually every signal bungalow, if not every one, but only carry data and not voice. The only railroads in the Chicago area that use a repeater on road is the South Shore Line and I believe the Metra Electric. Amtrak MOW uses one downtown and so does CPKC mechanical in Bensenville, just to name a couple others, but they aren't used for road. Usually these repeaters are pretty low power too.
Even if UP wanted to put a repeater on 62, it would require some complicated planning and tuning. 62 is the road channel for the south end of the Milwaukee Sub (quite busy) and the west end of the Geneva Sub (VERY busy) as well, meaning any repeater sites would either need to be tuned carefully for each line to eliminate interference from the others (highly directional antennas) or use separate PL tones/inputs for each line and expect crews to remember which set goes with which line, which isn't going to happen. Without that planning, it would basically be a free for all where no one would be able to get a word in edgewise, not to mention times when the VHF band comes alive in the spring and fall and ducting becomes a huge problem. It's possible, sure, but not worth the hassle or cost to install more equipment. The dispatcher can switch towers remotely so there's no need for everything to be on all of them all the time. If it ain't broke, don't fix it.
