They used some sort of adaptor.
The BU/Q cars use a van Dorn link pin coupler. The adapter
mates with the H2A head and presents a Van Dorn link which can
be mated with the coupler. The adapter breaks out the two
tappet valves from the face of the H2 coupling to individual
"glad-hand" hose couplings.
There was extreme difficulty getting them UN-coupled after the
lunch break.
the difficulty was in getting the BQs to take power correctly.
The Rockaways are nice, but not appropriate for this equipment.
1200 and 1400 series BU cars operated on those tracks from 1906
to about 1918 under a joint trackage rights arrangement with
the LIRR.