Doug Auburg commented:
I’m not an expert on the cars but after working for an electrical utility for 30 years I can offer some insights on utility practices.
Transformers are shipped w/o oil to minimize their weight. I don’t know how much these transformers from 80-plus years ago weighed but these days they weigh upwards of 300,000 pounds (or 300 tons – I can’t remember which), so any weight reduction they can achieve during shipping is a benefit. Now days they are dried and blanketed with nitrogen. Moisture is the enemy of transformer internals so every step is taken to keep moisture out.
So the tank cars in the train are most likely there containing transformer oil.
The cart is interesting as I’ve not seen them used in remote substations in the utility I worked for though they may have been. My employer had a cart at its servicing facilities (called untanking towers) where the transformer’s internals are lifted out to inspect and repair. Anyway, these carts are used to move the transformer around and minimize the number of times that riggers have to move it on cribbing. The transformers are too heavy to be lifted by a portable crane (especially in 1937). Fortunately, SCE had a fixed crane to transfer the transformer from the flat car to the cart. But they would use a rigging crew, cribbing and hydraulic jacks to move the transformers off of the cart and onto the substation’s concrete pad. In this case they apparently didn’t have a cart at this substation but they did have tracks in place so they shipped a cart along with the transformers and will return it to its storage location once they are in place.
I have no idea what they would have put in those tanks in the gondola at the front of the train. They could have transformer oil but they seem too small. On the other hand, I’m surprised that it takes 4 tank cars full of oil to fill the 3 transformers, but apparently it did. Remember that although the transformer tanks are large, they are filled mostly with electrical windings and supportive framework and the tank has not a bit more clearance from these internals than is required to provide a an insulating gap to prevent flashovers from the windings to the tank.
What I don’t see in these pictures are the porcelain insulators which are usually shipped in crates. I assume they must be in the gondola(s) out of sight?
Someone named Dean commented:
A standard 14000 KVA substation transformer empty weighs 53,000 lbs.
The 4000 gallons of oil weighs 33,000 pounds. Plus, the type of oil used back in that time until 1970 was PCB based. NASTY STUFF.