While riding the train at Starsburg I overheard to people say that they "Bottle the Air" when running the locomotive around the train. This saves them time. One of them said it is illegal and they are very surprised that they do this. He said if something were to happen while the locomotive wasn't attached that the train can roll into the NS mainline.
So can someone explain what bottling the air means? Is it illegal? If so would Strasburg actually do this?
The process of "bottling the air" is when the Engineer makes a substantial automatic brake valve reduction on the train line. Then, a crew member closes BOTH train line angle cocks at the rear of the locomotive, then cuts the locomotive off from the train. Thus, the train is left with a substantial, i.e. NOT an emergency brake set, while the locomotive proceeds to "run around the train" or do some other switching, leaving the train sitting there with the brakes applied, but NOT in emergency.
Yes, it is a "time saving" procedure, but potentially VERY dangerous, especially in freight service. That said, obviously the Strasburg Rail Road operating crew have this procedure down pat, plus the sitting train set is never really left "unattended", while the steam locomotive runs around the sitting passenger train set. Any member of the train crew remaining on board could easily put the train set into emergency. As far as "the train can roll into the NS mainline", that is not true, as the passenger train would only "roll" towards the freight cars spotted in the pick-up/set-out track adjacent to the main line track.