The picture you link to is probably exactly what the original author had in mind. It has mostly wooden bodywork and a metal subframe which in the event of a col

The picture you link to is probably exactly what the original author had in mind. It has mostly wooden bodywork and a metal subframe which in the event of a collision is given to riding up onto the carriage in front and killing everybody. They were literal death traps. In practice there were half a dozen non-structural reasons to move to less doors including automatic doors being much safer, disabled accessibility and simply that those trains were cold.