I have a MTH #30-4038-1 Pennsylvania, 6-8-6 Turbine Steam Passenger Ready-to-Run Train Set with protocol 2.0 from the year 2000 (see set photo). It has ABS plastic streamlined passenger cars (dome, baggage and end observation) which are lighted with interior seats (see photos). I want to populate them with passenger figures but can't remove the shells to get to the seats. How are the shells removed to get to those seats?