Steam shovel

Question for Swishy…
I watched a video of a restored steam shovel slowly move some dirt.
Wondered why there’s a steam pipe run all the way up to the top of the boom? Seems to be a small constant steam emission, not like exhausting from an engine.
Driver was working hard for not a lot of dirt moved.

Just a guess but maybe the pressure regulator/relief valve. Likely to vent any time so safely up out of the way?

I too wondered if it was a relief valve too. Usually relief valves vent directly, not via pipes which might impede the flow in an emergency.
Not a whistle is it?

Looking at others I think it is pressure regulator/relief. The fire can not be regulated with any degree of accuracy so the relief valve is going almost constantly. In a working machine the steam pressure must be a lot more than the minimum required to cater for changing demand without stopping halfway through a stroke. Only more modern steam engines and turbines have seriously looked at water recovery (although the idea goes back to Watt), the older stuff was total loss of steam/water so the fire had to keep producing through thick and thin. Old aircompressors had no shut off so they just ran on relief valves maintaining pressure through all the use variations. If you look at railway steam engines they nearly always have steam coming out of the pressure relief, particularly when they are not moving. How many movies have shown the bad guy blasted with steam as the pressure valve goes off as he is being chased by the hero in the rail yard.

The safety valves are beside the top of the boiler ,on the roof .........I didnt see what s mentioned,but it may be a cylinder drains from the crowd motor ,which is half way up the boom..............on a lot of the videos ,the crowd motor exhaust is to the top of the boom,probably so the steam doesnt cut visibilty of the operator............Every steam engine must have cylinder drains so water can be released......it will crack the piston or cylinder ends if trapped.

John the pipe extends right down to the boom hinge pins, must use some flexible hose back to the platform.
Yes you can see two relief valves poking out the top of the little shed.
I reckon Swishy must have surely driven one of these.
Whatever its purpose, it gets noticed. One of my grandkid’s bedtime story books is about a Machine-a-sauris. It has that same pipe puffing steam!

Anyone else here young enough to have grown up with Bill the Steam Shovel? :whistle:

I suspect there is a cylinder hidden in the boom for one of the functions and the steam is either a leak and/or drain left open. Lang, safety valves blowing off is a sign that the fireman has misjudged his fire. Excusable if train is held up at station but if always happening he is wasting fuel and risks being sent back to cleaning duties. That's in real life but in movies it is different, even throw some slack coal or tyres on the fire to make some smoke.

That Harman crane of mine was originally a shovel ,it had all the chains to drive the crowd there .............restoring heavy stuff is OK for someone with a float for their tractors ..........very expensive if you have to rely on others ..............collecting old draglines and shovels is really big in the US......people pay millions for them at auction there

If you look at this one I still reckon it is a relief/pressure valve



This is the Lake Goldsmith unit. Very detailed video and the steam blokes should be able to identify which valve is which.