Because of public pressure concerning neighborhood aesthetics, modern substation design tends to be less "in your face" than in years past. Typically the equipment is spread out and positioned much lower to the ground in an attempt to "blend in" with the surroundings. In order to maintain clearances, this usually requires more land and tends to be more expensive. Back in the Stone Age when land acquisition costs were a bigger factor, the equipment was more vertical so one had a smaller footprint and needed less land.
These newer 3Φ xfmrs are good examples of this "horizontal" approach - they all tend to have the same dimensions and usually fit nicely on a standard tractor-trailer rig.
Here is an old school 3Φ xfmr -







Basic shipping dimensions are 13'4" tall (without the bushings,) 6' wide and 11' long. And this is a fairly small substation xfmr - maybe 20MVA - but it is an impressive chunk of steel! The weight on the pad is about 87,000 pounds - 27,200 for the core and coils, 24,300 for the case and 35,300 for oil. The oil is about 40% of total weight, which is why they are shipped empty. Typically when a newscast runs a story about a "big" xfmr move they use the operational weight and not its "traveling" weight.

That is ABB's 800 kilovolt DC converter transformer. An amazing bit of technology.

Yeah it's the industrial transformers that are enormous, and these are the best ones for heavy haulage dios. :-D

I saw an article recently which gave the traveling weight of a transformer, something like 25% of the weight was copper.

Would love to build one of these puppies...