The last triple header I saw on the C&T had two engines on the front, five or six freight cars, then another engine and the regular coaches. The lead engines and the freight cars were cut off at Cumbres and the rest of the train went on to Osier. Don't know how the coming triple will be configured, but I'll give you a first hand account - I'll be on that train.
The engines are promised to be in Rio Grande lettering. Maybe I can convince them to "forget" to reletter them for the C&T after the special is over :-}