Range of Railroad Radios

How long is the range on a radio used by most railroads? How it this range extended to cover all of the railroads territory?

The railroad band only works about line of sight , with portables limited to maybe 2 miles and locomotive radio's about 10 miles, depending on hils flatland etc.
The Dispatchers have multiple bases at CP points, they can hear the trains and answer on this remote controled base via telephone lines.
When using a scanner you will often only hear dispatcher but not the train as they may not be in range of scanner.

Railroads do not use the same type or radio systems as Fire & Police departments. They use what is referred to as a "Simplex" or "Fixed-Base" radio system where the signal transmits from the hand-sets and goes only as far as the antenna from the radio will take it. Fire & Police[most at least] use[there are various types] what are called "Repeater" or "Duplex" radio systems, where the signal leaves the radio[the handset] on one frequency and then enters a repeater unit mounted on a tall transmitting tower and antenna and instantly retransmits that signal on a different frequency at a higher output signal from the antenna, called an "ERP" or effective radiated power. I wish railroads such as short-lines and regionals used this type of system, there are a few I know of, the Chicago South Shore & South Bend Railroad in Indiana and Kankakee Beaverville & Southern Railroad in [sort of] East Central Illinois.