How does a fireman on a steam locomotive know how much water is in a boiler when traveling up a steep grade?I have been in steam locomotives traveling up steep grades and the water in the boiler moves to the backhead and fills the water sight glasses all the way to the top.I don't see how the fireman would know when to add water since the site glasses are completly full all the way up the hill.I was told that was one of the reasons the Reading 2100 didn't really open the throttle on the steep grade up Tacoma hill as they would have a hard time caculating how much water to add in that time frame.
A second question I have is if for some reason you just left the injector on until you filled the boiler up with water all the way to the top would you get a increase in steam pressure or a decrease in steam pressure as the water rises?I'm guessing the steam would just be absorbed into the water and decrease the steam pressure.But considering steam has no where to go and is already in a pressure vessel is it possible it would be more compressed and rise the pressure?
Still the sight glass or try valves (the filter removes the other word). The main concern is to have water covering the crown sheet, which is the top of the firebox. A steep grade on a railroad is still only a couple degrees from horizontal, you'll get more fluctuation from acceleration and deceleration. A more likely reason the throttle wouldn't be open all the way on an upgrade would have more to do with traction, it's easier to lose footing and slip the drivers. The only time too much water is a problem is when there's a possibility of getting liquid into the dry pipe through the throttle valve, but this is less of a problem with a superheated locomotive.
To your second question, the injector won't fill a pressurized boiler all the way to the top. "Bottling up" a boiler is a common practice for overnight storage when the fire is banked on tourist railroads. When we do this on the locomotives at Steamtown, the pressure drops to around 50 PSI by the next morning.
Once the water is above the boiling temperature, as steam is used and the pressure drops, more of the water will flash to steam. Steam won't "absorb" into the water, it will condense back to water. Remember, water in the liquid state will not compress, water in the form of steam will compress.
Once you've been over the territory a few times, you start to get a pretty good sense of where your water is. Like what was mentioned above, starting and stopped bounce the water around in the glass far more than grades do.
Running an injector drops the boiler pressure fairly quickly as you're rapidly adding cold water into the boiler. If you need to run the injector, best practice is to give it short blasts rather than a long one, keeping the pressure rise and drops within a 5-7 psi window.
Thomas 9011 How does a fireman on a steam locomotive know how much water is in a boiler when traveling up a steep grade?I have been in steam locomotives traveling up steep grades and the water in the boiler moves to the backhead and fills the water sight glasses all the way to the top.I don't see how the fireman would know when to add water since the site glasses are completly full all the way up the hill.I was told that was one of the reasons the Reading 2100 didn't really open the throttle on the steep grade up Tacoma hill as they would have a hard time caculating how much water to add in that time frame. A second question I have is if for some reason you just left the injector on until you filled the boiler up with water all the way to the top would you get a increase in steam pressure or a decrease in steam pressure as the water rises?I'm guessing the steam would just be absorbed into the water and decrease the steam pressure.But considering steam has no where to go and is already in a pressure vessel is it possible it would be more compressed and rise the pressure?
Interesting subject. The picture below is the water glass of the 4294, a cab forward that normally ran on grades up to 2.4 percent. The water glass is marked to show the safe level of water for both the decending and ascending grades. Remember, this is a cab forward and the results are just opposite of a normal steam engine since the firebox is at the front of the cab forward. Other railroads might have used special marks for uphill and downhills for water sight glasses.
CZ
I never knew they had special marks for going up and down grades.That must have been a nerve racking job for a fireman with out those marks.I know some of those steam locomotives took a hour or more up some of those longer grades.Quite a long time to guess where the water level is.I know even on level grades if you have a steam locomotive clipping along at a pretty good speed on rough track the water in the sight glass goes from empty to full about every 2 seconds.
Thomas 9011 I never knew they had special marks for going up and down grades.That must have been a nerve racking job for a fireman with out those marks.I know some of those steam locomotives took a hour or more up some of those longer grades.Quite a long time to guess where the water level is.I know even on level grades if you have a steam locomotive clipping along at a pretty good speed on rough track the water in the sight glass goes from empty to full about every 2 seconds.
It is rather scary to see the water level jump up and down in the sight glass. No one wants to see that.
The AC-12's would be on the Hill for several hours on a good day. From Newcastle to Norden, the track distance is about 70 miles, but at an average of 20mph with a water stop, it could be very easily 3 hours on the grade. The fireman had to know his job and do it well.
Another fact that is not widely known. The Cab Forwards had pressurized oil tanks in the tender also since the fuel would not flow forward to the firebox by gravity on the grades. I believe they were pressurized to about 6 or 8 lbs.
I did not know they had two levels until I sat in the cab last year and looked at the details on the AC12. The dual markings for the long boiler and the climb over Donner certainly gave the fireman a better indication of the proper level for the water sight glass. If they injected too much water on the climb, the AC-12 would have started pulling water into the cylinders. The SP AC-12 had a fairly tall steam dome to prevent water from entering the steam pipe while going uphill.
I remember being with the Frisco 1522 crew during the NRHS convention in St Loius. We had just toped the aux and loco tenders off with water at Newburg Mo. Started on "Iron Mountain" grade to Rolla. We watched as the water in the sight glass looked like someone was draining it. The water was being used faster than we could put it in. By the time we got to Rolla. The aux tender was dry, and there was only less than 10 gallons in the main tender. She was VERY thrusty that day. As a side note: That was the first time I saw the exahst out of the stack so powerfull it was snapping tree limbs off the trees!!
Thank You.
Regarding this thread, and its topics, The Southern Rwy handled the 5.4 to 4.7, 3 mile grade at Saluda, NC by specially equipping the locomotives, thusly:
STEAM HELP - 2-10-2's were the mainstay and the class of Saluda's helper engines, serving the hill from 1917 to 1952. These Santa Fe types were special because:
1) They had water pipes running horizontally over the driving wheels to sprinkle water on tires while braking downhill to keep tires from over heating and falling off
2} They had second air pumps because of the excessive air brake demand; and
3 Both water glasses were extra long for safe reading on Saluda's steep grade.
STEAM MAGIC - Because the Santa Fe's were so heavy they were not allowed to operate between Hayne and Asheville, except at Saluda grade, until bridges were strengthened in the 1930's. How then did they ever get to Saluda in 1917? Assemble them there?
samfp1943STEAM MAGIC - Because the Santa Fe's were so heavy they were not allowed to operate between Hayne and Asheville, except at Saluda grade, until bridges were strengthened in the 1930's. How then did they ever get to Saluda in 1917? Assemble them there?
Steam could be moved cold without boiler water which reduced the weight. This was done with most new power being delivered over other railroads.
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