New Haven car with a zap

Here is photo of a NH transformer car. I assume the unit was to provide either temporary rerouting of power supplied from the Cos Cob power facility or a local utility. Was this a step down transformer on wheels for general usage or was this unit for connecting to the New Haven’s catenary system? This would be a good prototype to model. Dr. Frankenstein would have liked this car.

A portable Substation for use when demand exceded what the local substation could put out or cover for a
out of service substation on a branch. One side would be tied to high voltage transmission side/the other side would be
set at 11000 volts and feed to the overhead wire.

Are you sure it was for the New Haven/NYW+B or for the Connecticut Co?
Most larger trolley/Interurban systems had portable substation cars.

It’s been a while, but I think the caption for the photo stated it was a New Haven unit. That doesn’t necessarily mean the attribution was correct. The New Haven controlled The Connecticut Company for a while, so this could have been part of the unit’s history. What limited research I’ve done since your posting, is that the New Haven power plant in Stamford which provided 600V DC power to the New Canaan Branch also provide service to local streetcar systems. Whether this car served as a substation in this capacity during that era, I really can’t say. The New Canaan Branch converted to the mainline 11,000V AC in 1908.

Your best bet would be to head over to the Shore Line trolley Museum near East Haven Conn(aka Branford).
They maintain a large operating collection of Connecticut Co cars and a reference collection at their office/gift shop building.
the answer might be there,or check with the NHRHTA,they might have info as well.