I think we need the whole story, which we won't get.
In and around Dollywood, there are Ford E van cutaway tram tugs with a few matching trams in tow. These trams have air brakes- glad hands and all. So I'm guessing there's a air over hydraulic kit on these E van tugs. Yes I did sit in the first one, and did hear the air modulation, and a compressor cut in at the rear of the tug. The above can be a legit combo. Nice belly dump.