The vehicles were much quieter than I expected, although you couldn't pass through the middle section.
This is something new, or you misunderstood. I've passed through the engine/electrical cabinet compartment several times, although it's been 2 or 3 weeks since I've ridden the River Line. The signs that I saw said that you couldn't ride in the center compartment.
The ride was...slow and unimpressive. I guess it's better going up to Trenton...
The speed limit for street running in Camden is 25 mph, same as for non-rail motor vehicles. They do 60 mph between Bordentown and Trenton.
I also realized that service was half hourly ALL DAY LONG, including peak service hours...
They plan 15 minute headways during peak periods soon. The single track with passing sidings (north of Camden) is designed for only 15 or 30 minute headways. They can't run 3, 5, or 6 trains per hour; only 1, 2, or 4 (each way).
The PATCO cars are fine. The Budds are 35 years old and going strong. The railfan seat offers an excellent view.