Tugboat Annie was a miniature experimental Pacific locomotive designed by Curly Lawrence with the express goal of creating an ideal 4 cylinder engine with crank angles of 135 degrees for the smoothest possible power flow. He had already built a 4 cylinder loco with 135 cranks and asked his friend Harold Holcroft if it was possible to build a conjugated apparatus to run the inside valves. Holcroft said that it was possible but it would be better to have all of the valves be inline, which they were not for the completed loco. So Curly got to work on the locomotive the new gear would be suited for. He installed Baker valve gear on the outside motion which was unheard of in British locos up to that point. Once the engine was built with the same clearances as are on GWR and LMS flat 4 engines, he invited Holcroft to take a look and see what he could build. Holcroft came up with the perfect compact valve gear for the job.
I have found photos and a small amount of information about the engine that the valve gear was installed on.
“‘Tugboat Annie’, a 4 cylinder, 8 beat Pacific that was built by L.B.S.C. and has some features that exist in the British Railways engine ‘Britannia’, except that Britannia has only two cylinders. The type of valve gear that operates the inside cylinder valves was especially designed and tried out on this engine first before it went into full sized engines, and was by the famed designer Holcroft. So here is one rare instance where a small gauge engine was the ‘prototype’ on some of its features. From ‘The Live Steamer’, July-August 1951”
The status of this loco is at the moment unknown to me. I don't know if it still exists, nore if schematics of it exist at this time. If this loco still exists I hope to find it and study it. At the very least I want detailed schematics or literature on it that can illucidate its operation.
I have discovered a new photo of Tugboat Annie
I also found the very first real photo I have of its valve gear.
I have made contact with someone who knows that Tugboat Annie still exists and its whereabouts.