Welcome to RR. They are on an LTR system. If you have a trunking scanner, set up this sys: Industrial Electronics (Mountain Top) Trunking System,
They are on TGID 0-07-053 If you don't have a trunking scanner, you can listen to 463.90000 and hear them, plus fuel and concrete trucks. Actually, the LTA buses are on another LTR, but they are the ONLY ones on it, so you don' need a trunking scanner for them.