@jremington How would I go about transmitting actual data on radios like those?
@Robin2 @Arctic_Eddie @Musskopf Because of portability I'd like to do everything within my power to avoid using a repeater and, if possible, keep the antennas off the top of the train. This would never be used when the train is moving, only when an air brake test is being conducted (so when it's stopped at a railyard). The only reason I am slightly opposed to using an existing system is I'm not sure that every railyard this would be installed at would want another load on an existing network. Some may not have one, and those that do have them may be too complicated to interface with. Sorry if that doesn't make much sense- but basically for universality reasons the more independent this system can be the better. Especially if it doesn't require repeaters that would have to be collected and recharged every couple of days.
Thanks for all the input so far. I've also been reading up on LoRa radios which boast supposed ranges over a mile WITHOUT a line-of-sight all while drawing relatively little power (based on this). I saw another article somewhere which transmitted through nearly a mile of urban buildings from ground level to about three meters below ground without a repeater. Is LoRa a feasible system for my application?
Thanks again and best regards.