Surely trikes would be safeworking havoc, and doesn't it already take the bulk of the day for the main services to run the round trip?
I really think the big question is how many patrons are needed to make it sustainable, break even, or just keep the loss to an acceptable level? I suspect that its probably a huge number when you factor in the increases in wear and tear on the equipment and infrastructure, fuel consumption, staffing etc needed to maintain a larger patronage.
Wacky, left field, foamer idea...Is the driving compartment of DP13 a total loss as per the rest of it? If not maybe they could purchase that and build a DP outline short wheelbase car?