This is one of the 2 ft gauge cars. The Wikipedia "London Pneumatic Despatch Company" article I read says says "A capsule conveying up to 35 bags of mail could make the short journey between terminals in one minute." and elsewhere says the distance was 1/3 mile, which is a 20mph average, and the Living Age report quoted says " ~ at a rate, we are informed, of twenty miles an hour."
