The steam safety valve goes way back to the 1400s. Conical plugs were hammered into pressure vessels before the spring type safety valves were invented. Sometimes we forget that there were steam plants long before the locomotive.
Pete.
It probably would be the safety valve, they go back to the very earliest steam engines in the U.K.
Interesting little narrow-gauge engine!
Blue Mountain Locomotive — Fort Walla Walla Museum (fwwm.org)
I don't know if you're only talking about yard engines or specific types, but the engine here in town is an O-6-O without flanges on the center tires.
It's a 1877 Porter locomotive at the Fort Walla Walla Museum. If anybody has information on this and similar engines it would be nice to hear from you. One of the few photos we have shows two things on top of the condensing dome. I assume one is the whistle, would the other be a relief valve? When did they start using safety valves?
Dr_BullittWere the real locomotives built like this to navigate tight curves?
another approach for dealing with tight curves was to apparently to use smaller drivers spaced closer together. compare the 0-6-0 wheels bottom left. note how the B8 uses smaller drivers and spacing than the B7. the maximum track curvature for the B8 is 100` while it's 125' for other 0-6-0s
greg - Philadelphia & Reading / Reading
O-6-0's were mostly yard engines. They had a sloped tender to allow the crew to see behind when switching cars.
wrench567That must have been one really sharp turn. The locomotive looks like a USRA design. But with slide valves and an extra sand dome.
Yes it was a sharp curve. The prototype 0-6-0 is at the Illinois Railway Museum. And it does have a blind center driver.
Steam Engines - Illinois Railway Museum (irm.org)
Here is a diagram of the curve:
Dave H. Painted side goes up. My website : wnbranch.com
wrench567 A prototype 0-6-0 with blind drivers? No. If anyone knows of one please post it here. https://www.thehopkinthomasproject.com/TheHopkinThomasProject/CoalFireIronSteel/Appendices/CatasauquaIndustryResidences/CatasauquaIndustries/Railroads/YurkoArticle.htm LNE #206 gets a drink from the enclosed Reading water tank at West Catasauqua on October 20,1936. In the latter years of steam, the 206 and 207 were the only locomotives to go directly to the Reading yard as they were equipped with blind center drivers to take the sharp curve at the LVRR crossing. (Rod Dirkes)
wrench567 A prototype 0-6-0 with blind drivers? No. If anyone knows of one please post it here.
https://www.thehopkinthomasproject.com/TheHopkinThomasProject/CoalFireIronSteel/Appendices/CatasauquaIndustryResidences/CatasauquaIndustries/Railroads/YurkoArticle.htm
LNE #206 gets a drink from the enclosed Reading water tank at West Catasauqua on October 20,1936. In the latter years of steam, the 206 and 207 were the only locomotives to go directly to the Reading yard as they were equipped with blind center drivers to take the sharp curve at the LVRR crossing. (Rod Dirkes)
That must have been one really sharp turn. The locomotive looks like a USRA design. But with slide valves and an extra sand dome.
Thanks for furthering my knowledge.
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
A prototype 0-6-0 with blind drivers? No. If anyone knows of one please post it here. If the track was that bad, then a 0-4-0 would be used or possibly a rubber tired car with couplers would be used too.
Point to remember is that a 'poley' (driver without flange and with greater lateral tire width) has much worse adhesion patch than a typical 'coned' flanged driver. So you'd keep the three pairs flanged, perhaps with some lateral, rather than treat it like a long 0-4-0 with blind drivers in the middle.
Keep in mind that even what we think of as wide and sweeping model curve radii are ridiculously sharp by real-railroad standards. So it isn't surprising that a toy engine expected to negotiate 15"-18" radii in HO would have only the 'end' driver pairs flanged.
Not all, but many were. Especially where tight curves would be encountered. Dan
All of my HO 0-6-0 locomotives do not have a flang on the middle wheels. Were the real locomotives built like this to navigate tight curves?