As the numbers of these are shrinking, perhaps just a handful of units, UP is running a local out of Phoenix, east on the line to Mesa, McQueen, Gilbert etc., and for the last week the consist has been a pair of GP units - the “patched” GP60 1919, and an unpatched GP40-2M 7235! I saw this consist again tonight - at the Dobson crossing in Mesa it was eastbound with the local - including a pair or vintage passenger cars (one Rock Island, didn’t get the names of the two - I assume these are heading for the Chandler Railway Museum). About 30 minutes later the two units were westbound running light. The GP60 has a K3 horn on it, but the 7235 still has its P3 and you don’t see or hear many of those around any more.
SP 183 turned up yesterday on NS near 47th Street in Chicago. It was sandwiched between UP 6763 and UP 5598 on Detroit Edison empties returning to the PRB.
Most of the unpatched SP’s seem to be the AC4400CW’s in the 100-378 series.