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After inspection, mechanical work, and a new paint scheme, Reading, Blue Mountain & Northern 4-6-2 No. 425 headed trains on the Lehigh Gorge Scenic Railway on August 22-23, when NKP 2-8-4 No. 765 stopped in Jim Thorpe on her return from Pittston. Her valves were shopped at Strasburg last year. Now she is "dead square" and she uses less coal and water. The new RBM&N herald on her tender resembles the Gulf, Mobile & Northern herald on her Baldwin 1928 builder's photo.

Reptd425&765JimThorpe 004

 

Here she is marching out of the former Jersey Central yard at Jim Thorpe

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Reptd425&765JimThorpe 020
Originally Posted by Steaming Jon:
Two things really impress me about 765 climbing that hill...

1: the dead-square sharp as a knife exhaust

2: the safety lifting roughly six minutes into the video
I was always taught that constantly lifting the safety is wasting water and fuel. In years past, whenever I lifted the safety, while on the road, the Engineer had unkind comments toward me.

What a locomotive and crew!!!!!

 

Originally Posted by Steaming Jon:
Two things really impress me about 765 climbing that hill...

1: the dead-square sharp as a knife exhaust

2: the safety lifting roughly six minutes into the video

What a locomotive and crew!!!!!

We were purposely firing "over the pops" on that climb because we needed the added pressure in the cylinders to keep moving. When you are down on your knees at 1 mph with the throttle wide open and reverse gear down in the corner, it's the fireman who determines whether you keep going or not!

 

Is it wasteful of water and coal? Yes.

 

Was it necessary in order to keep from stalling? Yes.

 

We felt it was worth it to waste a few gallons of water and a few pounds of coal to keep from stalling and tieing up the railroad for several hours.

Originally Posted by Matt A:

Rich - Approximately what boiler pressure were you operating at?

Maximum working pressure of the NKP 700 class was 245psi. Thus with at least one safety open, 765 would have been at no less that 246psi. Remember that the steam locomotive is essentially a heat machine, i.e. the higher the temperature of the steam entering the valves/cylinders then the higher the horsepower. It may not sound like much, but an extra one, two, or three psi boiler pressure, and the increasing steam temperature through the superheater units, would provide measurable higher temperature steam into the valves/cylinders. Thus, higher horsepower!

I assume the higher temperature steam condenses less during the piston stroke causing the average pressure on the piston during the pistons stroke to be higher thus making more horsepower.

 

Do you ever have problems with steam condensing in the cylinders when operating at such a slow speed?

 

Is NKP 765 always run at 245PSI or is it run at a slightly lower pressure in normal operation?

Matt- here's my understanding... Higher temp = more energy = more expansion = more power. Condensation in the cylinders only happens when they are cold (train stopped). The engineer opens cocks on the cylinders when first starting out to allow the water to escape. Usually within a few revolutions of the drivers the cylinders are warm enough that the steam no longer condenses. The cylinders are kept warm by the steam even at low speeds.

Just to be clear, I was not running the locomotive on this climb. 765 engineer Gary Bensman was at the throttle and Jason Sobcynski was firing.

 

And yes...someone DID get a shot right at the top of the hill...I did! Here's a video clip I shot with my I-phone right at the top of the hill where she finally starts to accelerate. You'll note that Gary gives me a thumbs up as they go by the camera.

 

Jason is purposely crowding the fire, thus all the smoke. He's crowding the fire so he can fire "over the pops" providing more than 250 psi of steam for Gary to work with.

 

 

That Magnificent MachineTM of ours got down to less than ONE MPH, but she never slipped and she never stalled.

Last edited by Rich Melvin

Rich,

Was the engine on sand anywhere on the climb? And do you know the percent grade? At low speed, near stall, the engine was not making much drawbar HP, but was without question at maximum boiler HP, all of it going into generation of tractive effort (i.e. drawbar pull). And do you have an estimate of trailing tonnage?

My guess is that, in steam days, the engine's tonnage rating on that grade would be such that the train's minimum speed would be in the ten or 15 mph range.

 

Originally Posted by Hudson5432:

Rich,

Was the engine on sand anywhere on the climb?
Gary had to use sand only at the bottom of the grade on the connecting track where the NS track guys greased the rails. Once clear of that area, there was no further need for sand. The rail conditions on this day were very good.

And do you know the percent grade?
It varies between 1.5 and 1.7%. And the 1.7% section is on a curve just past Plymouth Road. The train got down to .68 mph in that curve. The video clip in the OP's post shows this.


And do you have an estimate of trailing tonnage?
27 cars, average of 85 tons per car = 2,295 tons.


 

Originally Posted by NKP Muncie:

Very nice video, Rich. Were you hand-holding the camera? If so, quite steady. Sometimes I though the only disturbance was from breathing! Yours, not 765's

Shot with my iPhone 6, hand-held. You just have to know how to do it.

 

Last edited by Rich Melvin
Originally Posted by Steaming Jon:

       
Here's a question... I'm guessing the train was stopped, or going very slow, at the bottom of the hill. If you came into the bottom of the hill at speed, let's say somewhere around 50mph or so, would she have maintained that speed up the hill? (Thinking of the relationship between horsepower and speed)

       


I think my question got lost in the discussion...

The 611 may have been just a touch faster up the hill with the 80,000 pounds of TE, but if you were able to push 765 up to the same 300psi boiler pressure, the 765 would have probably been a touch faster too. This pull is possible because these two engines have 69-70 inch drivers, whereas something like a 80 inch drivered UP FEF or a Santa Fe 4-8-4 probably would have stalled, IMO. A Texas 2-10-4 with 63 inch drivers would have marched right up it.

 

 You assume a K4 with a booster would be faster, that would be if the booster engine doesn't start slipping and you have to shut off the throttle. There's a video of 2716 having problems on a grade down south, where the booster causes more problems than it solved.

Originally Posted by steam fan:

The 611 may have been just a touch faster up the hill with the 80,000 pounds of TE, but if you were able to push 765 up to the same 300psi boiler pressure, the 765 would have probably been a touch faster too. This pull is possible because these two engines have 69-70 inch drivers, whereas something like a 80 inch drivered UP FEF or a Santa Fe 4-8-4 probably would have stalled, IMO.

 

I wouldn't assume that at all.

 

A Texas 2-10-4 with 63 inch drivers would have marched right up it.

 

 You assume a K4 with a booster would be faster, that would be if the booster engine doesn't start slipping and you have to shut off the throttle. There's a video of 2716 having problems on a grade down south, where the booster causes more problems than it solved.

 

Originally Posted by Steaming Jon:
Here's a question... I'm guessing the train was stopped, or going very slow, at the bottom of the hill. If you came into the bottom of the hill at speed, let's say somewhere around 50mph or so, would she have maintained that speed up the hill? (Thinking of the relationship between horsepower and speed)

The train was stopped right at the bottom of the hill. We than had a 5 mph restriction on the connection track on the wye, which is where the hill starts.There was no run for the hill at all.

 

If the 765 had hit this grade at 50 mph, my SWAG estimate is that she would have gone over the top at 35-40 mph. MUCH more horsepower is available at 50 mph than there is at 5!

I really enjoyed the video .

 

I'm from a small railroads town, My dad was a steam  hogger , so were my uncles and most families on our street worked for the railway.  Our town had all the railroad facilities , turntable, round house,  ice house, sand house, big machine shop, Car dept. and a stock pile of coal that was about 30  feet high and about 1/2 mile long. 2 yards,  station with restaurant built on a curve  . dispatching office and of  course the superintendents office building .... which leads  for me  the following questions... Is it hard on a engine to have the reverser in the corner with full throttle  for extended periods of time?.... and in the video would the fireman  also have manually throw coal in the firebox. (chunks going up the stack?)  I believe there's a pedal that opens the fire box door when the fireman is ready to  throw coal in with the shovel. Why does the fireman open and close the door between  each shovel full?  

I don't suppose the fireman would be too happy if the engine was a hand bomber which leads to another question.. if the stoker failed could the fireman actually  hand bomb the engine or is it just too big? 

 

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