Now a 155 is.... Two 153's coupled together, but without the middle cabs, ad 153's where modified from the 155's? right?
Pretty much. In total 42 155s were built (as part of the super sprinter order that included the 156s) then later on 35 sets were split in half and converted into 153s (hence why one cab is tiny that end was originally the middle of the 155 set) to replace the single car bubbles (classes 121 and 122). The only reason that there are still 7 155s is that WYPTE didn't consent to having their units converted.
