Simply enough... the Drawing Room with its three births was sold as a Section fare, nothing more. Little if any changes were made to the room... but this is the first time I have read something about a bathroom being sealed off.
Probably the best place to get more answers would be the
Passenger Car List at Yahoo
! Groups. Most of what I have learned over the years came from information shared on the List
!!!The distinctions from the MT 12-1 would be the non-pediment roof (common to 24__ series) and double windows at the aisle window locations.
The Plan 2410H cars introduced the pediment ends and they had a carbody that is a fairly close match to that of the MT Plan 3410 car with only a few dimensions being different. It was the Plan 2410F from 1916 that introduced the window pattern used on the 2410H and 3410/3410A cars and even some of them were rebuilt with pediment ends. Minor differences in some measurements was the result of the Plan 3410 cars being roughly a foot plus longer than their predecessors but it would not be too much of a stretch to use the MT model to represent one of the earlier cars.
The biggest problem with using the MT Plan 3410 car is that the model has AC air ducts and AC equipment under the carbody, much of which was not present on
most of the cars that were reassigned to "Tourist" service. My
Plan 3410 Roster page details which cars were involved... searching for "TC" in the Notes to the right of every listing will help folks find which cars were converted as well as some dispositions, where known...
It may not be too unreasonable of a kitbashing to use the MT 3410 with the pediment ends being replaced with those of the twin-windowed coach with the roof of two models being adapted to fit the sleeper. Have not investigated the viability of such but it can be done... the problem really is that N is so much smaller to work with so it is a bit more challenging to do such conversions.
One thing that is badly needed for modeling a troop train is a non-AC roof... that in itself would go a long ways towards making tourist cars a whole lot easier... heck, us modelers could easily remove the AC equipment from under the car (for placement on an MT coach???), though that is something else that can be addressed by a manufacturer.