How fast could the atmospheric railway go?

a Three car set( present day Path trains are seven cars) accidentally Hit 80 Miles per Hour ( one mile in 45 seconds_) and this was ratified in Guinesss as a form of RR speed record. service speed was much slower- about 45 tops- again showing a resemblance to modern subways. accidentally too much power was ( dumped) into the start manifold- power commands were telegraphed- the operator did not have the precise control of the cars as does a modern subway motorman. so it was unplanned- but did hit 80 Mile speed!