150-Mile-Per-Hour Steam

[cordon]

Dear Railroad Friends,

After an e-mail exchange with Mr. Bergstrom, I am taking a chance on trying to re-open the discussion on high speed steam locomotives.  I read the whole thread and hope I have the gist of it.  If I missed something, please feel free to fill in.

The central question was, could coal-fired reciprocating steam engines pull a railroad train at 150 miles per hour (MPH)?  Several points were:

Unbalanced forces from the drive rods at high speed would produce unacceptable wear and tear on the tracks.

It might not be possible to stoke coal fast enough for such a speed.

A few examples of high-speed steam locomotives achieved speeds in the range of 125-140 MPH.

A steam locomotive that takes advantage of modern technology would be far better in all respects than the newest steam locomotives that we are familiar with, just as a modern aircraft is much better than an aircraft dating from the 1950s. 

Greasing and oiling would be automatic, instead of manual. 

High-speed freight cars would need disc brakes, like those on passenger rail cars. 

 

I offer here my comments.

Balancing a piston engine of normal design is difficult.  Six cylinders are the fewest that we can balance well without resorting to a lot of extra weights and shafts.  Because the usual locomotive arrangement has one cylinder on either side of the locomotive a rocking motion occurs.  The quarter-turn relative setting of the cranks, which gives smooth power delivery and enables self-starting, makes the rocking motion worse than if the cranks were offset by a half turn or not offset at all.  Therefore, I believe it would be best to try to balance each side independently; that is, treat each side as a single cylinder engine with respect to balancing.

For a single cylinder, we can achieve a good balance in the direction of the piston travel, or we can balance it well at right angles to the direction of piston travel, but not in both directions at the same time, unless we add a countershaft that carries an additional counterbalancing weight.  This would increase the complexity of the design, but results may make it worth it.  This type of added counterbalancing weight/shaft appears on several modern single-cylinder motorcycle engines, where it greatly reduces vibration felt by the driver and passenger.

Even after adding this additional countershaft and weight, we find that we have treated only the "primary" balance that occurs at the speed of the crank rotation.  Because the piston driver rods operate at a variable angle with respect to the line between the crankshaft centerline and the piston, there exists an additional component of unbalance at twice the speed of the crank rotation, called "secondary" unbalance.  Secondary unbalance usually creates a vibration much smaller than that coming from primary unbalance.  If we cannot accept it, however, we have to add another countershaft/weight running at twice the speed of the main crank.

It seems to me that there are solutions to the balance/vibration issue.  What isn't clear, however, is how much the addition of more heavy rotating parts would complicate the engine design and how much it would cost.

My personal observation of passing trains leads me to think that most of the damage to track comes from the vibration and pounding created by wheels passing over rail joints.  Since continuous welded rail (CWR) came into common use mostly after the end of steam locomotive use, I don't think we have much data on how badly steam locomotives cause wear and tear to CWR. 

With respect to the application of modern technology to locomotive design, I feel that items like sealed bearings, automatic control systems, high-strength steels and alloys, and many other technologies would give us a very different and much improved locomotive if we started over with a new design.

I didn't see any comment about condensers in the old thread.  My belief is that any modern steam locomotive will have to use condensers to get full efficiency and to conserve water.

I think it will be a huge challenge to meet pollution requirements with a coal-fired engine.  But I don't know much about the technologies involved, so I can't say very much.

I don't recall seeing anything on ash disposal in the old thread.  That's a definite cost that railroads would have to handle. 

One last comment - on disc brakes for freight cars.  My view is that the main problem with freight car brakes is avoiding wheel lockup and skidding, not the "power" of the brake itself.  My understanding is that railroads set freight car brakes to avoid wheel lockup, with the result that the brakes are seriously underused.  I believe that a freight train consisting mostly of cars with anti-lock brake systems (ABS) would be able to stop in the same distance as a passenger train. The main advantage of disc brakes is the ability to make multiple stops from high speed in a short period of time, a requirement that freight trains don't have.

Even with disc brakes we still have the basic limitation of the low coefficient of friction between steel wheels and steel rails.  The type of brake applied to the wheels cannot improve on that limitation.

 

 

[marknewton]

A few observations...

Unbalanced forces from the drive rods at high speed would produce unacceptable wear and tear on the tracks.
Not an insurmountable problem. Modern steam was generally well balanced for high-speed running. A new-build loco would benefit from computer-based balancing analysis not available to the old-time engineers and designers.

It might not be posible to stoke coal fast enough for such a speed.
It would be entirely possible, but why bother? Go for oil-firing.

I didn't see any comment about condensers in the old thread. My belief is that any modern steam locomotive will have to use condensers to get full efficiency and to conserve water.
Condensors are best used on stationary steam plant. A modern loco would not benefit from condensing, since the boiler would no longer be self-regulating.

I don't recall seeing anything on ash disposal in the old thread. That's a definite cost that railroads would have to handle.
See above - go for oil firing.

Cheers,

Mark.

[Modelcar]

....Comment:

Regarding pulling freight trains at that speed....I was thinking our previous discussion was pointed towards high speed passenger train running.  Not specifically, just thinking in that direction.  But then again....I suppose it was {in part}, about saving oil as fuel to haul freight and passenger consists.

I wonder about pulling general freight trains at such speeds with center of gravity at different heights from different kinds of revenue loads and perhaps other factors.  Even the wide different shapes of various freight cars.

As for using oil as fuel, isn't that what part of the thought using steam is....to get away from consuming oil....?

But one other thing...it is an interesting subject as long as we all treat it in a civil manner.

[marknewton]

As for using oil as fuel, isn't that what part of the thought using steam is....to get away from consuming oil....?

Even a coal-fired steam loco consumes oil.

Mark.

[wjstix]

As for using oil as fuel, isn't that what part of the thought using steam is....to get away from consuming oil....?

Even a coal-fired steam loco consumes oil.

Mark.

Many railroads used oil rather than coal - Great Northern, Union Pacific, Southern Pacific, others. With a mechanical coal stoker (which many modern engines had) you could feed coal to engine to go however fast you wanted I'd think, though it might be easier with oil.

[diningcar]

Further on Modelcar's comments:

Currently there is not a track configuration (of significant length) which would handle 150 MPH, and for freight trains it would take a drastic redesign which would require ROW acquisition that would be strenuously resisted.

When European or Japanese high speed trains are cited we should examine what they were created for (passengers), and the fact that freight moves much shorter distances there so the need for high speed freight is not a significant motivator.

[Modelcar]

....I would wager there could be much more support in this country for a "modern steam engine" to produce speeds for passenger and maybe some categories of freight trains in the 100 to 120 mph speed range. Perhaps more value for dollars spent to achieve such.

One would think "that engine" would be less difficult to design and approve and build.  That also goes for ROW too.

[Anonymous]

I welcome the topic of modern steam but, as presented in this thread, the topic seems bifurcated.  I see the two objectives of 150 mph, and the return to steam as being distinctly unrelated and not at all dependent upon each other.  So as an extreme example, it would be like asking could we bring back steam and change the track gauge to 66 inches?  I noticed this same bifurcation in the previous thread about 150 mph steam.  I had assumed that the high-speed rate was only introduced to exemplify the perhaps perceived underrated capabilities of steam, and not to offer 150 mph as a real objective.  But the high-speed-with-steam concept did develop in the discussion, and the point was never quite clear to me.  If there were a demand for 150 mph, it could be achieved with any kind of motive power.  I don't see that steam offers any particular advantage in achieving it.

It seems to me that the most obvious reason to bring back steam is that it can run on coal instead of oil, and thereby reduce the cost of fuel.

A secondary reason in the minds of some is that dieselization was a mistake and that steam should be brought back as a remedy.

To some of your points:

I believe a properly designed stoker that could handle the 150 mph speed would be rather easy to achieve.

Fully automatic lubrication seems reasonable to expect.  Moreover, sensors could detect temperature and vary lubrication to match power transmission force if needed.

Balancing may be an issue at 150 mph, but at today's typical speed, I think that balancing could be perfected so as to reduce track wear to an acceptable level.

I too have wondered about condensers and their tradeoffs.

Regarding pollution and ash:

I understand that there is a process in which coal is micropulverized and then the ash is removed by an electrostatic precipitator, resulting in clean coal, which produces no ash when burned.  I suspect that this pre-processing of coal would also go a long ways toward making the pollution more manageable.

[TH&B]

What about using 3 or 4 cylinder engines for 150mph?  Wouldn't they be able to balace better and create more power then 2 cylinder engines? Also small high speed drivers like the N&W  J class ?  Modern materials and technoligy could be applied.  Light weight materials and a streamlined train. 

[greyhounds]

I believe that with enough resources ($$$) and time a 150 MPH steam locomotive could probably be built.

The question is:  Why would you spend resources and time building such a thing?

It is difficult, if not impossible, to build or expand a coal fired electric generating plant in the US today.  The traditionally regarded pollutants can be dealt with, but when you burn carbon (coal) you produce carbon dioxide.  The Powers That Be won't currently allow this.  Why would they allow coal to be used in locomotives?

There is virtually no market for 150 MPH freight.  The problem with rail freight is keeping it moving at a reasonable speed, not the top possible speed.  A 40 MPH average from Sioux City/Council Bluffs to Harrisburg would produce a 36 hour transit and be service competitive with truck movement for the large volume of fresh meat shipped out of Iowa and Nebraska to the northeast.  That's all that is needed. 

For passengers higher speeds are needed.  But they can be produced with existing trains.  Heck Fire, the Illinois Central ran the Green Diamond (Chicago-St. Louis) at 117 MPH in the 1930's.  Again, the problem is not top speed, but maintaining a good average.  This will take investments in mundane things like track structure, crossing protection, etc.  No new motive power is needed.  And if such power were developed, it would be useless without these more mundane investments.

[trainfan1221]

As I said in the first discussion, even if it were possible, where would you run it?  Not too many lines are out there ready for 150mph service.

[Modelcar]

....Were the J class units considered to have "small" drivers.....?  It just seems a bit surprising.  Some of those engines did operate over 100 mph from reports I've seen.

[selector]

Smaller would be more accurate, Quentin.  UP's Challenger only has 69" drivers, and it can do pretty close to 80 mph in regular service.   I am unsure if they have capped it at 70 mph in keeping with the "top speed in mph is equal to the diameter of the drivers in inches" rule.  But the J only had 70"* and we know it could easily handle speeds well above that.  The Pennsy's Duplex often ran in excess of 100 mph to make up time with its 80" drivers.  I am quite certain most modern Northern type 4-8-4 steamers regularly flirted with 90-100 mph speeds when they had been delayed.

*Edit- corrected using steamlocomotive.com's figures.

[cordon]

Upon review of the old thread (BTW, it is here), I can't find the comment about the disc brakes.  The OP, however, opened the discussion with a question about coal-fired steam engines.

I think the old thread covered the issues of, "Where could we run it?"  But I also think that a newly designed steam engine would enjoy the same advantages at 70-100 MPH as it would at 150.

With respect to oil, I believe conversion to oil, whether steam or diesel, occurred because the price of oil in the 1940s and 1950s was way below the price for equivalent energy from any other source, including coal. I remember Diesel fuel at about six cents a gallon when gasoline was about 15 cents/gal.  IMHO, the very low price also caused many streetcar companies to convert to Diesel buses and was a significant push behind the explosive growth of trucks in those decades (along with the Interstate Highway System).  Diesel was king, all of a sudden.

Most people with coal furnaces in their homes were converting to oil as well.  Later on, they converted again to gas and electricity.

If the new steam engine does not use a condenser, the railroads will have to rebuild the extensive water supply facilities, including the "scoop and trough" installations to refill tenders with water at speed.  They have taken down all that stuff.

On multi-cylinder approaches, four cylinders can get a better balance than two, and six cylinders can achieve a theoretically complete balance without any extra "monkey-motion" countershafts/weights.

One other random thought: I think just painting a steam engine some color other than black would greatly improve the public's perception and reaction to it.

 

 

[Anonymous]

I don't think that pushing the envelope higher on speed records was an attribute that followed the progression of steam development evolution.  In other words, the modern 4-8-4s could surly exceed 100 mph, but so could 4-4-2s and even 4-4-0s of the 1880-1900 period.

[CNW 6000]

Steam and new technology are great...but as was said...why is 150 mph necessary?  If the technology is so much better then build one and let's compare it in service against a modern diesel.

[Modelcar]

.....Good info, thanks selector.

Edit:  Was just thinking, I've stood right beside those "drivers" and don't remember of them being small.

[marknewton]

As for using oil as fuel, isn't that what part of the thought using steam is....to get away from consuming oil....?

Even a coal-fired steam loco consumes oil.

Mark.

Many railroads used oil rather than coal - Great Northern, Union Pacific, Southern Pacific, others. With a mechanical coal stoker (which many modern engines had) you could feed coal to engine to go however fast you wanted I'd think, though it might be easier with oil.

Stix, I'm aware of the widespread use of oil firing by US railroads, and elsewhere in the world. My point was that on a conventional coal-fired locomotive, oil is still consumed as a lubricant. Even allowing for grease-lubricated rods, axleboxes, etc, you're still using oil to lubricate the valve chests, cylinders and some appliances. I don't know if it is technically possible to do without it - I doubt it somehow.

Cheers,

Mark.

[marknewton]

If the new steam engine does not use a condenser, the railroads will have to rebuild the extensive water supply facilities, including the "scoop and trough" installations to refill tenders with water at speed.  They have taken down all that stuff.

A condensing loco would still require watering facilities. A condensing loco is not a closed system - there are still losses to be made up, so there would be no saving on watering facilities. And if railroads were to start using steam again, other replacement infrastructure would be required as well, since very little that is usable remains today.

IMO, the objections to condensing on a railroad locomotive are numerous. It adds a considerable amount of complexity, weight, and decreases efficiency. If you look at any of the locos that were built as condensors, you'll see that they were intended for very specific roles where the trade-offs were tolerable, and in many cases they were quickly converted to non-condensing when the need disappeared.

For my money, the way to go is an oil-fired, non-condensing compound engine.

Cheers,

Mark.

[marknewton]

On multi-cylinder approaches, four cylinders can get a better balance than two, and six cylinders can achieve a theoretically complete balance without any extra "monkey-motion" countershafts/weights.

Do what most modern designs did - concentrate on rotating balance, and let the reciprocating balance be taken care of by the mass of the loco and tender, using a proven method such as a Franklin radial buffer.

One other random thought: I think just painting a steam engine some color other than black would greatly improve the public's perception and reaction to it.

The blokes who have to keep them clean might differ with you on that one. :-)

Mark.

[TH&B]

.....Good info, thanks selector.

Edit:  Was just thinking, I've stood right beside those "drivers" and don't remember of them being small.

 

I did stay small, they're not exactly tiny , but compared to 100mph + if it realy could go that fast , the drivers are relatively small. Another example would be the Evening Star type from England, an even later model with smaller wheels looking like a freight engine but could acheive 90mph. And for what I read withinterest was that it would stand in for A4's and keep schedual, mostly because of better acceleration and ease of maintaining the 90mph.

 

http://en.wikipedia.org/wiki/Image:92220_Evening_Star_(Dave_Cooper).jpg

 

http://upload.wikimedia.org/wikipedia/commons/8/8b/Union-of-South-Africa.jpg

 

http://en.wikipedia.org/wiki/Image:NW_611.jpg

 

All pics from Wikipidikidia

[Modelcar]

....Now those wheels on 60009 engine are awesome....!  That is rather large by any measure.

Just seems wheels that large would be very difficult to get to a good balance.  That engine must have had to have a push to get started....

[tomikawaTT]

A few items:

• The N&W J was actually designed for 140MPH, 70 inch drivers and all.  The N&W Railway (infrastructure) limited their top speed to 90MPH.  The one recorded 110MPH run took place on the PRR, strictly as a test.
• Back in 1970 or so Bill Withuhn designed a four-cylinder steam engine that virtually eliminated dynamic augment.  Unfortunately, nothing like it has ever been built.
• Almost every truly modern steam locomotive had automatic oilers.  On the J, even the bell bearings were automatically oiled!
• I'm certain that a mechanical stoker could be built to feed coal into the firebox just as fast as it could burn.

An interesting possibility would be a Garratt with really tall drivers - possible because the drivers don't restrict the design of the boiler.

Chuck

[marknewton]

Another example would be the Evening Star type from England, an even later model with smaller wheels looking like a freight engine but could acheive 90mph. And for what I read withinterest was that it would stand in for A4's and keep schedual, mostly because of better acceleration and ease of maintaining the 90mph

The 9Fs were renowned for their fast running on weekend and holiday trains on the Somerset & Dorset. They were an exceptionally free-steaming, free-running engine, which is why they could sustain 90mph. The boiler proportions and front end were about as close to the ideal as any BR standard design.

Mark.

[marknewton]

....Now those wheels on 60009 engine are awesome....!  That is rather large by any measure.

They're 6'8", or 80" diameter. They only look really large because the A4 is a very small loco by US standards. The railways in the UK had a very restricted loading gauge.

Just seems wheels that large would be very difficult to get to a good balance.  That engine must have had to have a push to get started....

Quite the opposite - bigger wheels are easier to balance. Also bear in mind that the A4s are a three-cylinder engine. They certainly didn't "need a push" to get started - they're surprisingly toey things when you open the regulator. My depot was host to a similar loco in 1988/89, and we were all surprised at how well the thing performed.





Cheers,

Mark.

[marknewton]

An interesting possibility would be a Garratt with really tall drivers - possible because the drivers don't restrict the design of the boiler.

Absolutely, Chuck, that's where my thinking is headed. One need only look at the Algerian Garratts to know this idea has potential!

Cheers,

Mark.

[timz]

The N&W J was actually designed for 140MPH, 70 inch drivers and all.

How is an engine "designed for 140 mph" different from an engine of the same wheel arrangement and nominal TE "designed for 100 mph"?

[Modelcar]

.....80" drivers under any size engine would look large to me...I just look around in my office here and note that a standard door frame is 6' 8"......I picture a wheel of that size and bingo....it's big.

[selector]

I do the same thing, Quentin.  I could fit my rather small frame between the outer rim surfaces of a Challenger's drivers quite easily....diameter-wise I mean.  I'm not thin enough to actually squeeze between two drivers.

If you have ever found videos on youtube of UP 844, with its 80" drivers, and then found one with it doubling Challenger 3985 at track speed, you can see a marked difference between the two (oops, three) sets of drivers.  The Northern-type prances along in a stately manner while poor ol' 3985 churns like a mud-racer.

-Crandell

[tomikawaTT]

The N&W J was actually designed for 140MPH, 70 inch drivers and all.

How is an engine "designed for 140 mph" different from an engine of the same wheel arrangement and nominal TE "designed for 100 mph"?

Counterbalancing, cross-balancing and the stiffness of the lead and trailing truck centering devices (which help to control the effects of dynamic augment) - for openers.  I'm sure Mark Newton could add to this answer.

As for, "Who said the J was designed for 140MPH?"  The people who designed and built them.

Chuck