A) Carrier insistence, in case 4014 breaks down. It's older than you-know-who.

B) The passenger cars' heating and air conditioning systems run on electricity. A team's last passenger trains to rely on steam heating and steam-powered air conditioning were 81 and 82, the Silver Star. That practice stopped in 1981. The diesels can provide head end power for these operations. 4014 cannot.

Positive Train Control prevents train-to-train collisions or derailments caused by excessive speed. When a steam engine moves on public railroads, they usually have an 'escort' to provide the service.
I learned about this when the Norfolk and Western 611 was returned from the Strasburg, Pennsylvania rail museum to its home in Roanoke, Virginia several years ago.

Hasn't 4014 been so equipped? I'm sure I can dig up some in-cab video.

Even back in the '90s, UP locomotives had a transponder positioned above the rails right behind the pilot. It was there to pick up signal indications, even though it could not interact as PTC does.

I hope Hiawatha Pete shows up, as he is well versed in these things.

611 is running in Virginia this month. It's making a trip through Charlottesville.

Thanks, and good afternoon.