What was it maximum speed ? --89.49.180.75 (talk) 07:44, 28 May 2008 (UTC)Reply
- There is no credible technical evidence--certainly not from New Zealand Railways--of the maximum possible speed of any of the NZGR steam locomotives (e.g. Ab, Ja, Ka classes) that had 54-inch driving wheels and a 21-inch piston stroke. All maximum speed claims on this subject that have been written by contributors in Wikipedia have originated from New Zealand rail enthusiast sources who perpetuate the myth and legend written--without acceptable provenance--about the performance capability of these locomotives. It does a great disservice to Wikipedia and the people who use its resource that this furphy is able to be foisted so easily on the readership. What CAN be stated, in answer to the question, is that at 60 mph these locomotives would have been running with more than 6 piston strokes per second. What chance that they could have been made to go faster than this even if you assumed perfect tangent track (3ft 6in gauge). I think it can be accepted that anything above 63 or 64 mph would have been a mechanical impossibility. This stuff really needs to stop. Throttleer (talk) 14:57, 14 August 2023 (UTC)Reply
