The term "shotgun exhaust"...

Yes, that was one TOUGH pull. She got down to less than ONE MPH, but never slipped and never stalled.

I think we can safely put this one in the "don't try this at home, kiddies" file

 

---PCJ

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.

 

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

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!!!!!

 

It is true that a lifted safety is wasted steam. I am still impressed by the fact that pulling that hard with the throttle most likely on the roof she can still make more steam than she is using...

Well, THAT is what "SUPER POWER" by Lima was/is all about.

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.

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?

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)

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.

Rich,

 

Excellent work. You're to be commended for maintaining forward momentum. Great to see the 765 pull that grade.

Yup, this only builds more appreciation for those  Van  Berks !  In some ways this is not too surprising, as the C&O K4 routinely wrestled with 140 car coal trains.  Those machines had boosters for when the going got too rough.

Hey, did anyone get vid of the train at the actual summit, where Rich and crew are down to the absolute lowest speed?  That would have to be really something !

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.

Great video Rich, thanks for sharing!!!

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.