Those don't appear to be the GP40FH-2s from the SLRG. They may carry SLRG reporting marks, but so did a lot of the IPH equipment that never saw Colorado rails.
The SLRG got two PRLX (ex-CSXT) SD70Ms a few months back that seem to be doing most of the work now. The GP40FH-2s out here are either in NJT silver (4141) or in Adams State College green/black (4138). When I went out to shoot the last day on the BMLP a few weeks back, I caught an SLRG concert train with E9A #100 in the lead and one of the SD70Ms trailing.
It does make me wonder how much longer passenger service will continue. Typically receivers are tasked by the court with preserving the value of the company, and if the passenger trains are losing money I would expect they'll come to a quick end.