Not every railroad would do this, but a number of lines would also make changes to the running gear to improve balance and obtain higher rotational speeds with reduced dynamic augment. From what I've read this most often would involve new drivers of some sort, such as Box Pok or Baldwin discs, sometimes for all drivers and sometimes just for the main driver. About as often as not, a rebuilt locomotive along these lines might get new lighter-weight rods. None of this stuff would raise tractive effort or horsepower in themselves, but they could allow whatever horsepower that was available to be used in higher speed ranges than the stock locomotive, along with reduced track strains and maintenance.

There might be tender modifications, too, usually in the form of a larger tender to get more range.

Sure, lots of locomotives with Type A superheaters had multiple valve front end throttles. You don't necessarily need a Type E superheater for high superheat either. While it was the most common way of doing it in the U.S., the Chinese (for instance) just install very large Type A superheaters (look at the tube arrangement in an SY compared to a ~1920's US 2-8-2). Basically, you squeeze all the flues and superheater units you can fit into the boiler. You can also increase the surface area of the existing superheater arrangement by installing Houlet type elements or similar. Of course, the number of superheater elements is also limited by how big of a superheater header you can fit in the smokebox, and that space has to be juggled with space for the new exhaust and the feedwater heater.

The big thing about super heaters is that they should have a relatively big cross sectional gas flow area and short length rather than small gas flow area and long length. This prevents pressure drop between the regulator and the cylinders.

I thought some railroads had maintenance issues with the Type E superheater units as opposed to the Type A? The L&N in particular, with their 2-8-4s had issues with unit burn out, I thought I read somewhere.

Was this a problem elsewhere?

As Dave said, if the throttle can't be left wide open, what's the point? Unfortunately I don't see many railroads in this country that require engines to be operated efficiently, and the ones that do, don't. I would be curious to do real economic surveys on fuel savings with superheated vs. saturated engines, including cost of water and water treatment. I'd really like to see an operation that required a fleet of engines with all the best ideas for efficiency, but they still looked like steam engines.

I also applaud the use of whistles.

If you want to really improve on the efficiency of a steam locomotive, just get yourself one of these: http://en.wikipedia.org/wiki/EMD_FT ;-)

Well, John......sustainability is always worth considering. There's no reason why - once you have measured the outside paramaters of your specific operating practice - you can't design and build a system better tuned to support just that use efficiently. Minimizing costs over a 15 year operating period will leave more in the fund for the next overhaul. You may have to make some alterations if your needs change - like adding a car to the consist, or going to a fuel with a different caloric content or rate of combustion - but if you know your metrics you can make design changes that are appropriate for the change.

I think there are a lot of things that can be done just for economy - no matter what your need for efficiency from an operating POV might be. If you waste 20% of the steam that goes through the throttle due to the design of the rings and packings, and it costs only marginally more to retrofit a better design, you will reap the benefits every time you move under steam. If you build a front end that gets you the right amount of vacuum with less back pressure, you won't need as much steam in the first place. If you can replace that very inefficient turbogenerator with some thing else to power your lights that uses waste heat you are losing anyhow to make electricity you also don't need to hear that whine all day.........or pay for the cost of the steam used or generator maintenance.

Ed's solution has economic merit but isn't mission sensitive and is of course no fun.

dave

From the linked reference on the FT:

“The roof is a more reliable indication; FTs had four exhaust stacks along the centerline…”

Did the FT units have four exhaust stacks?

I was thinking about the "Historic artifact" bit, I thought about the 3 N&W 4-8-0's recently saved, the N&W did not buy 0-8-0's till late in steam.
They kept a good supply of the 4-8-0's to do all the local switching and some branch runs. They had a long run of 40ish years of service. Thru time they got some workovers/fixes. It would be no stranger for this supposed 2-8-2.
The 4-8-0's were not retired because they were old, but because newer steam engines with better steam tech came out among other reasons. But the 4-8-0's were still stalworth workers which is why they were kept. N&W was able to keep them in condition. And I still say if you really wanted to you could fully restore one of those saved 4-8-0s to fully operating condition.

Doing this 2-8-2 work in theory or real, you should have a backup engine for your "business" in case there is a problem as you will have customers looking for their deliveries.

As you may know the progression of technical advancement for the steam engine reflects a lot of whats transpiring in this thread. And recall the ACE project and there are some working projects out there to make a modern steam engine, their just working in quiet secrecy, recall some college bought a Santa FE 4-8-4 to study it and look into modern steam.

If you ever really do this you could with todays computer technology place heat sensors etc etc around the engine to study how its performing.

Right now I am not in line with a "virtual" valve system like what we do in today's cars, its heavy machinery, if the system crashes, theirs no function.
Keep it mechanical.

Yes, FT's had four exhaust stacks.

Steve

Since the poster mentioned a Mikado as the example, I'd like to bring GCR 4960 in on this. A 1923 Baldwin, she was built with a modest (30") combustion chamber. During her big rebuild in the late 90's, her original circulators were removed and 8 transverse arch tubes put in their place. I and another mechanic ratttled these during a boiler wash once so I got a good look at both ends and in the firebox.

As far as Superheat, I have witnessed her steam temp as high as 705 degrees on the road. They have a sustained 6 mile 3% grade and sand at every opportunity.

She also received a Lempor Exhaust a few years ago as did stablemate 2-8-0 29.

There's likely a point where the payout efficiency on projects diminishes, but I think here's a pretty good example of a mid steam era Mike that has been well modernized.

Shame that she was built for a granger road and didn't have more weight on the drivers. She could have benefitted from another 10 lbs or so on the boiler. Just my opinion here.

Tom- you guys at GCRR did some impressive work on those locomotives. More recently, they've added feedwater heaters (Chinese copies of Worthington SA's) to 4960 and 29 as well.

The 4960 is indeed a good example of what I'm proposing. Most likely, the GCRR did not consider weighting the frame or increasing her steam pressure..or maybe they did, and we just don't know about it. Te other thing is we don't know what she was capable of in her former configuration compared to what she can do now..

We never considered the boiler pressure on GCRR. It's always a case of doing what you can rather than what you want. The two Lempors basically doubled the vacuum for a given back pressure and where both designed in a week end.

What ever I make no secret that the biggest gains to be had are through re draughting.

The equalization on 4960 was changed a little for the '99 steam season to put more weight on the drivers. Unfortunately, we ran into a period where the quality of the hard grease that was purchased was not as good as in prior years, so the pins went back to their original positions account of the high temps on driver bearings.