I went back and checked the time tables again. In 1949 there was a register book at Carbon Jct., but it was only signed by nos. 215 and 216 (in other words, all scheduled trains signed in). Extras were not required to stop and sign the register.
After the "San Juan" was taken off, the Carbon Jct. register book was removed.
If freights were required to stop and sign the register, the "right over and wait" wouldn't be needed, but it wasn't. That was what I was missing.
Brother Templeton, keep 'em coming - I enjoy dissecting the old records like this.
JAC