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| Joe G Collias, The Search for Steam, Heimberger House Publishing , 1972 |
What might be one of the world's most ungainly-looking rail things, Motor car No. 1004 waits at the depot for passengers. McKeen built about 150 of these railcars between 1905 and 1917 and the Chicago Great Western railway bought four of them. They were powered by internal combustion engines with power to only the front axle. Marine engine-style, they had no reverse, they had to be stopped, the cam adjusted to running the other direction and restarted, which was not popular with their crews. Nonetheless they put in decades of service, this shot was taken in Iowa in 1948.
The McKeen trademarks were the ships-prow front with porthole windows. Over the years they were repowered, the pilots changed, more equipment was stacked on the roof and some were converted to flat or round noses. More here.
Update; Dennis sends a link to pictures he took of a restored McKeen at The Nevada State Railroad Museum in Carson City, Nevada. It's beautiful! Thank you, Dennis.
7 comments:
Do you know if the engines were 2 stroke or 4 stroke cycle?
To run in reverse, "the cam was adjusted". I know that some 2 strokes can start and run in reverse if the ignition is retarded enough (adjust the IGNITION cam),
but those were big engines for 2 strokes. It's hard for me to imagine a reversible 4 stroke, but not impossible.
Jack from Illinois
Correction: ADVANCED enough.
Apparently here were a variety of engines used, but I haven't found a reference to 2 stroke, I'll assume the 6 cylinder McKeen engine was four stroke. The concept of reversing an engine to reverse was common with marine engines of the time. I went down a rabbit hole with discussions of running McKeen engines on "Distillate" apparently a variable kind of fuel that wasn't heavy oil. Google 'McKeen's 200-horsepower distillate engine". Primitive times in internal combustion engines!
Now I'm trying to imagine a lever-actuated two-position cam gear. I do know efficient variable valve timing has been around for decades...:-)
I did some internet surfing, and I now believe it probably was a 4 stroke cycle engine. One way to design a 6 cylinder engine to be reversible, instead of just 12 cams on the camshaft, put 24, with a sloping surface between each pair. Design the camshaft so it can be slid either forward or backward, so it will position only half the cams under the cam followers at the same time. The cams, of course, are ground different.
Jack from Illinois
The reverse running was standard in the marine engines at the time so they had something worked out. Remember, this was right at the very beginning of IC engines, they probably only turned 1000rpm and may or may not have had atmospheric intake valves. More info required!
Another method. Instead of two sets of lobes, how about a camshaft gear that was somehow dog clutched to the actual camshaft. The camshaft could be locked into either of two positions. Now I have to go find old marine engines to look at:-)
I forgot about atmospheric intake valves. Problem half solved!
Jack from Illinois
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