Continuing yesterday’s thought about steel and curves, here’s a photo of Newark Penn Station from a recent trip. That’s the main roof over the platforms: Newark Penn is an elevated through station. The tracks to the east are on a bridge crossing the Passaic River, and are some twenty feet above grade, so the main station rooms are below the tracks and platforms. The station itself is a combination of classical and Art Deco architecture, a mish-mash that sounds bad but is quite good looking in practice. The Pennsylvania Railroad took operations very seriously, and the station was designed to cause as little delay as possible for express trains from the south and west heading to New York’s Penn Station, about eight miles away, but it’s hard to look at that roof and not see some frivolity.
There’s no particular reason for the roof to be supported on curved transverse trusses or for the longitudinal arches. That’s all steel framing and the building was constructed in 1935, when steel design was quite mature. The same loads and the same basic roof geometry could have been supported on straight beams and straight-line trusses. But the space would have been boring. Here’s a view over two of the tracks:
Note that the openings in the solid roof over the platform are glazed, while the center openings over the tracks are open. The main-line passenger trains were electrified twenty years earlier, but I think there may have still been coal-fired engines on some lines and pulling freight. The main point of interest in the second picture is the shape of the transverse (green-painted) girders spanning over the tracks. They’re curved, so that they’re higher in the middle than at the ends, and their depth varies so that they’re deeper in the middle than at the ends. Again, this was not necessary, but it makes them look better. It’s also worth pointing out that the curves were made easier to fabricate by the fact that these girders are built up of plates and angles, rather than being one piece. The difference in labor and materials in building them to those gentle curves versus straight is small, while building up such beams today would be a lot more work than simply using deep wide-flange beams.
The mix of architectural styles is nicely complimented by the use of curved steel to roof over dead-straight tracks.