Traction Engines = Steam Car. already up there. unless you think it needs further distinction as progression of the technology, traction engines being large tractor things and steam cars being like jalopies. I think what's already up there fits the idea of steam cars fine.
Also steam cars didn't go all that fast because they didn't have very good gearboxes. Even the earliest steam cars had humongous amounts of torque while only going a few hundred rpm. And by the 1920s the Doble steam car could go from stone cold to ready in a maximum 40 seconds.
"The 1924 model Doble Series E steam car could run for 1,500 miles (2,400 km) before its 24-gallon water tank needed to be refilled; even in freezing weather, it could be started from cold and move off within 30 seconds, and once fully warmed could be relied upon to reach speeds in excess of 90 miles per hour (140 km/h). In recent years Doble cars have been run at speeds approaching 120 mph (190 km/h), this without the benefits of streamlining, and a lighter version of the Series E accelerated from 0 - 75 mph (121 km/h) in 10 seconds." - Doble steam car - wikipedia
The difference engine was a calculator, the analytical engine was an incomplete design for a computer. Computing Engines is the tech that you get for building the difference engine wonder, or whatever starts off the steampunk age, symbolizing the widespread adoption of mechanical computers and all the changes to society that stems from that. It's why Civ 4 vanilla doesn't call the computers tech "ENIAC" or "Harvard Mk 1" or Nuclear Power "Calder Hall Nuclear Power Station"
and can i please please get some feedback on what to do with "subterranean exploration". It or something like it, is kind of important if steampunk is to point back to modern seismology at some point.