I have noticed recently while running steam on a train simulator that the locomotive was equipped with a live steam injector and an exhaust steam injector. I can assume the live steam injector takes steam from the turret, while the exhaust steam injector recycles steam being exhausted from the cylinders. If this is true, how is the steam collected for such use?

There is a pipe off the exhaust manifold bellow the blast pipe. This feeds the steam to the injector. It also needs some live steam from the boiler. The injector will only work when the engine is under power so the injector will cut out when steam is shut off. The reason they are used is for efficiency.

To extend on this a bit:

American locomotives by law had to have two methods of getting water into the boiler, one of which was a (live steam) injector. The other system was usually, on modern power, some form of feedwater heater. An exhaust steam injector, sometimes jocularly referred to as 'the poor man's feedwater heater', is a method of implementing the feedwater heating without the separate mixing, cold- and hot-water pumps, etc. of a typical closed or open feedwater heater system.

An injector can be made to work on comparatively low pressure, if sufficient mass is available, and the ESI makes use of this when the locomotive is running. The nice part is that both the water mass and the latent heat of vaporization in the exhaust steam are conserved in the Rankine cycle, just as in an open-type FWH, but with less componentry. (The ESI itself tended to be a complicated piece of machinery, but had few actual moving parts aside from valves and adjusting wheelslevers -- there are some good diagrams in the Encyclopedia of World Railway Locomotives by Ransome-Wallis)

Historically, an issue with ESIs is that they involve considerable care to run -- they will 'break' if there are significant changes in steam flow when running with exhaust steam, and may have to be manipulated fairly often if there is appreciable stopping or drifting. This would be more of a problem with large American-size power, probably, than it was in Britain or other places ESIs would have been used. Notably, Union Pacific, which had long stretches where high power could be maintained, used ESIs quite happily.

There's a fairly extensive discussion on the problems with one exhaust steam injector in a November 1978 Trains magazine article on the Missouri Pacific's Franklin Type A poppet valve equipped 4-6-2, #6001. It was equipped with an Elesco ES exhaust steam injector. The article related that while running at speed, a reduction in cutoff of even one notch could cause the injector to "break" and lose flow. The engineman that related this story theorized that the reduced back pressure allowed by the poppet valves contributed to the problem.

In the US, they were often called "a poor man's feedwater heater".

Didn't they change over to live steam automatically?

Ed King's "Big Boy or Big Mistake" article in Trains said that Big Boy crews tended to stay with the live steam injectors to avoid all the ESI trickery which defeated the purpose. He also questioned why UP, usually buying the best of everything, didn't just go with a regular FWH.

(His main point about UP 4000's was that they should have been built with smaller drivers to give greater pulling power in the speed range they were normally used at as an 80 MPH top speed was unnecessary. That's actually something I've always thought about and agree with.)

Steve

I thought I had read in one of the Kratville UP motive power books that there simply wasn't a good place to mount the equipment for a FWH on a Big Boy. Of course, that didn't stop other railroads with large articulated power from doing so. So, I wonder what the reasoning was.

Either way, to try to allude that the 4000s were a "big mistake" seem to ignore the years of service these locomotives put in, in demanding terrain. Could there have been design differences? Sure, but that is simply Monday Morning Quarterbacking.

King repeats that same thing in the current special issuse of Trains Mag.

Having talked to a number of people over the years who fired and ran the UP engines, here's what I can offer.

The Elesco TP exhaust steam injector on the 3900's and 4000's actually worked pretty well. I never heard any of them complain about it or claim they always used the Nathan 4000 injector that was on the other side of the cab. The shop vets say they were fairly simple to maintain as well. Erosion of the nozzle seemed to be the most mentioned, and that was taken care of by simply replacing the nozzle, which was done either in the roundhouse or right on the service tracks.

UP's 800's, however, came from Alco with a Sellers exhaust steam injector, and you will be very hard pressed to find anyone who will have a good word to say about this thing. It required a detailed, precise starting sequence that involved 2 levers and a valve and
any misstep meant the process had to be begun again. It was, indeed prone to break at the most inopportune times, such as coming into a station stop. Showering waiting passengers with was not a good thing.

This was cured by replacing the Sellers with Worthington SA's.

As to the mounting of a Worthington SA, UP had had all they wanted of this on the earlier Challengers. The hot water pump was mounted on the pilot deck of the front engine, which gave it a very solid base, but also required a lot of piping and flexible joints to get water to it from the cold water pump under the cab.

Some railroads addressed this issue by hanging the hot pump on or under the smokebox.
If mounted at the side of the smokebox, this required a "scallop" in the smokebox to get clearance, which in turn was in the way when it was time to pull flues.

Another issue is that the hot pump, when it's on, creates a pounding with each stroke. That is why it's better to have a solid mounting for it, as it is trying to tear itself off the engine with each stroke. Broken mounting bolts, cracks, etc. could be a problem, and whatever it was mounted to (if not the frame) had to be reinforced.

This is the first I have heard of exhaust injectors, would be interesting to know what engines did have them. I don't think any engine could be without the live steam injector, I presume you get the exhaust injector going enroute. I would think theoretically the steam has been thru the hottest throttle steam and superheated so you could get better steam off the exhaust than where the Live steam may collect its steam.

The White Pass, ordered their #72 and 73 Baldwin 2-8-2's with the Sellers exhaust steam injector and removed them farily soon.

The Uintah did the same thing, and might have used them a little longer than the WP&Y did, but in the end, same result; removed.

The US based 3' gauge rr's must have had too many load changes, throttle and/or johnson bar adjustments, etc.. to allow the contraption to function. The 3' gauge also never had a Feedwater heater, so thats another contraption that US narrowgaugers don't have to worry about.

As for surviving locomotives that had excause steam injectors, here's what I know:

Union Pacific 4-8-8-4s

Union Pacific 4-6-6-4s

C&O 614 had a Nathan one in service, but it was removed when in storage. When it was reactivated by the C&O for a traffic surge, it was replaced by a non-lifting injector.

The post-war Canadian Pacific G3 4-6-2s had them.

Any others?

CNR 6400 (4-8-4)
CNR 6069, 6077 (4-8-2)
CNR 5700, 5702 (4-6-4)

And likely several others.

CNR 6060 used to have one but it was replaced with a live steam injector

While CN used Elesco Feed Water Heaters on many of its Northern and Mountain type engines, several classes were equipped with Exhaust Steam Injectors including the U-2-h, U-3-a, U-3-b, U-4-a, U-4-b class Northerns and the U-1-f class Mountains, and on the K-5-a class Hudsons

Not to mention the infinite variation amongst all of its smaller power.

I see them working better on trains that have long runs with limited variables of throttling.
Injectors are tricky things to get going, if you vary the steam input that blows the settings and it won't pump. I've run injectors on steam traction engines, its a balance, but when you hit, its perfect.

The UP Big Boys and Challengers make perfect sense to have them, with long west coast runs and depending on grades reasonable minimal throttling, you could have loooong stretches of level track, may as well kick in that injector, these engines have to keep that coal moving and that water.

I would think you would need some kind of steam pressure regulator to keep the steam input as steady and regular as possible.

You can add the Soo Line #1003 with an Elesco that works like a charm. According to documentation the live steam is regulated down to about 6psi and that input pressure is what the injector is designed to operate with. When the engine is working hard enough to produce greater than 6psi back pressure there is a sensing valve that switches the feed from the live to exhaust steam supply. As the engine is throttled back and drops below that level of back pressure the sensing valve automatically cuts it back to live steam with only a slight spit of water out the overflow. mld

I believe 614 actually had a Hancock unit that was called a feed water heater, but was actually more of an exhaust steam injector.

What sim are you playing that has that extensive of a level of detai?