Locomotive Johnson bar - photo

[Altair]

Locomotive Johnson bar or reversing lever.

Fullsize image: https://diqn32j8nouaz.cloudfront.net...r_fullsize.jpg



Previously:

Machining a locomotive coupling rod in the 1930s - photo
Steam locomotive conjugated valve gear animation - GIF
Walschaerts locomotive valve gear operation - video

[hemmjo]

LOTS of parts there to ponder. Each with its own function. Some smooth, some rough, some cast with smooth flowing lines. Certainly not as complex as some machines today, but for their time... fascinating. Makes one wonder about all of the hands and minds that conceived and assembled the beast.

I used to visit an office waiting room, on a regular basis, unfortunately spending hours waiting there over several years. In that room was a large, very fine quality, framed, pencil sketch showing 3 drive wheels, with all rods the rods and bars levers, the steam chest, etc. I used to pass the time studying that image. After a couple of visits, I realized that the artist, as fine as their work was, had missed some detail. It appeared me, the way the drive rods were shown, they could not pivot as required in operation. Over the next few visits, I tried to find a way to explain away the error but never could. The sketch disappeared during a remodeling of the offices, I sure wish I had a copy of it.