Bill
My railway is 3.5 inch scale. ie 3.5 inches between the rails. Or put another way, 1/16 scale. When I build anything for my railway it is 1/16 of full size. Thus a 27 foot coach plus buffers would be about 29 feet. 29 feet into inches is 348 inches , divide that by 16 gives a length of 21.75 inches which is 1 3/4 inches to big.
Mike