Steam Locomotives

[coaldust2026]

I have read that steam engines were particularly damaging to rails.  Can someone explain why this was so, and what was done to improve the situation.  Thanks very much.

[Lost World]

Some classes of large, modern steam locomotives were known to be hellish on the track, usually ones with especially powerful piston thrusts, poor counterbalancing (many of the early 63" and 69" drivered Berkshires and Texas types fall into this category) or a long driving wheel base.  The biggest problems occurred on curvature, where such engines could throw the track out of proper alignment on an almost daily basis, keeping section crews hard at work.  Damage to the rails wasn't so much the problem as the alignment; however, it wouldn't surprise me if rails in these spots wore out quickly and had to be replaced more often.

Line improvement projects were the best cure for this problem, eg. straightening of curvature.  This was usually done in order to raise speed limits for passenger trains, but an added benefit was less wear on gentler curves of track.  Also, as modern steam grew more modern throughout the late 30's and into the 40's, lighter reciprocating machinery became the rule, and this also helped to reduce the hammer-blow effect of their powerful piston thrust.

But really it all came down to track maintenance, and in the steam age section crews worked problem areas every day.  This was just another high-maintenance aspect of the steam locomotive, and one more reason for their replacement.  Diesels are much more forgiving on trackwork.

[daveklepper]

Bascially, the answer is that an electric motor is a close-to-constant torque and power device whereas a reciprocating steam locomotive, no matter how well counterbalanced, is an intermittant torque and power device.   And a diesel-hydraulic is still closer to constant torque and power than a two cylinder or even a four cylinder steam locomotive, assuming the diesel in the diesel hydraulic has more than four cylinders.   Just as a perfectly tuned eight cylinder auto engine is smoother than a similar four cylinder.

[Tim Burton]

Where is Michael Sol?  He has stats showing it really wasn't any harder on rails than diesels...I remember reading them in one of the 80 page threads about Steam v. Diesels.

[MichaelSol]

"Other Considerations

"Diesel locomotive design has proved, as electric locomotive design has proved in Europe, that high speeds can be safely made with locomotives having small-diameter driving wheels without the necessity of idle leading axles. Thus all of the locomotive weight may be used for adhesion.

"Small diameter driving wheels, and lower centre of gravity do produce greater track and rail stresses. Rail 'burns' from slipping driving wheels are more prevalent with diesel operation than with former steam. It is often claimed that the change from steam to diesel has reduced the cost of track maintenance. Maintenance of way costs have been carefully examined over the period studied to verify this claim. No indication can be found that the change in the type of motive power has produced any savings in this field. Such costs have increased slightly.." H. F. Brown at p. 273-274.

Brown, H.F., "Economic Results of Diesel Electric Motive Power on the Railways of the United States of America," Proceedings of the Institution of Mechanical Engineers, 175:5 (1961).

<> 

[J. Edgar]

 

 another factor in track maintaince is ballast cleaning......steam locomotives spew cinders and clunkers as much as smoke and steam.....these cinders land on the ballast and the rumbling of trains turn them to dust.....this dust is caustic and when mixed with rain water made a corroded mess of codelines and track circuts......as such the large track gangs and early powered ballast cleaners worked putnear year round

[TomDiehl]

"Other Considerations

"Diesel locomotive design has proved, as electric locomotive design has proved in Europe, that high speeds can be safely made with locomotives having small-diameter driving wheels without the necessity of idle leading axles. Thus all of the locomotive weight may be used for adhesion.

"Small diameter driving wheels, and lower centre of gravity do produce greater track and rail stresses. Rail 'burns' from slipping driving wheels are more prevalent with diesel operation than with former steam. It is often claimed that the change from steam to diesel has reduced the cost of track maintenance. Maintenance of way costs have been carefully examined over the period studied to verify this claim. No indication can be found that the change in the type of motive power has produced any savings in this field. Such costs have increased slightly.." H. F. Brown at p. 273-274.

Brown, H.F., "Economic Results of Diesel Electric Motive Power on the Railways of the United States of America," Proceedings of the Institution of Mechanical Engineers, 175:5 (1961).

<> 

Unfortunately, automatic wheel slip control for diesel locomotives was invented after 1961. Steam locomotives still don't have it.

[wjstix]

A couple of stories I remember reading - one was about the Milwaukee 4-4-2's used on the Hiawatha. With their 84" drivers they could go incredibly fast, but supposedly no one ever tried them at full throttle so we'll never know how fast. One problem was with ballast, at 100 mph a steam engine tended to blast ballast off the track, with enough force to make it dangerous. Second, there's a story that in the fifties the Missabe had to run a mail train to Duluth...this was a very high priority as the mail contract was a major source of RR income...and no engine could be found. At last a big ex BL&E 2-10-4 with 63"drivers and huge siderods was found to be the only engine available, so they put it on the train and told the engineer to go as fast as he could to make the scheduled time of arrival no matter what. The next day, they found that the rails were wavy - every place the siderod had slammed down, it lowered the track a little. I guess that whole line had to be redone.

[GP40-2]

A couple of stories I remember reading - one was about the Milwaukee 4-4-2's used on the Hiawatha. With their 84" drivers they could go incredibly fast, but supposedly no one ever tried them at full throttle so we'll never know how fast. One problem was with ballast, at 100 mph a steam engine tended to blast ballast off the track, with enough force to make it dangerous. Second, there's a story that in the fifties the Missabe had to run a mail train to Duluth...this was a very high priority as the mail contract was a major source of RR income...and no engine could be found. At last a big ex BL&E 2-10-4 with 63"drivers and huge siderods was found to be the only engine available, so they put it on the train and told the engineer to go as fast as he could to make the scheduled time of arrival no matter what. The next day, they found that the rails were wavy - every place the siderod had slammed down, it lowered the track a little. I guess that whole line had to be redone.

That's funny, I don't recall any stories of ballast being blasted off the tracks when Amtrak runs at 150 MPH on the NEC.

The B&O would run 64" drivered S1  2-10-2s at over 70 MPH every day. They would also run their 64" drivered 2-8-8-4 EM1s that would dwarf a BL&E 2-10-4 at 70+ MPH in express service. I don't recall any complaints on the B&O of rails being "wavy" on a daily basis.

[tomikawaTT]

The key to rail damage at speed from a steam locomotive was asymmetric balance. By the end of steam, the most modern locomotives were using light alloy siderods, while other advances in counterbalancing had reduced the imbalance to the point that the N&W J could theoretically run at 140 mph without unduly stressing the rails.  (The J, with 70 inch drivers, routinely cruised at 90mph and was once run at 110mph.)

I recall a tale that rail damage appeared on one division of the NYC, and was eventually traced to a locomotive that had lost some of the lead from one driver counterweight, resulting in a dynamic imbalance of over a ton!  When that loco had its drivers reweighted and rebalanced, the imbalance was reduced to less than 150 lb and the damage stopped happening.

OTOH, the total imbalance in an electrically driven axle can be measured in ounces, and not very many of them.

Chuck (modeling Central Japan in September, 1964 - with coal burners restricted to 70kph)

[daveklepper]

In my way of thinking, the fact that wear on track has increased only slightly since the steam days is actually an indication that yes, steam was harder on the track.   Because there has been a truly terrific increase in loaded freightcar weight with the improvement in rail weight and track structure only a fraction of this increase.   At the Boston and Maine, during the period of dieselization, reduction in track maintenance expense did occur on the routes diesilized.

[wjstix]

That's funny, I don't recall any stories of ballast being blasted off the tracks when Amtrak runs at 150 MPH on the NEC.

Yes, that was my point. 

The B&O would run 64" drivered S1  2-10-2s at over 70 MPH every day. They would also run their 64" drivered 2-8-8-4 EM1s that would dwarf a BL&E 2-10-4 at 70+ MPH in express service. I don't recall any complaints on the B&O of rails being "wavy" on a daily basis.

I'm sure that's true.  The BLE/DMIR 2-10-4's weren't designed for fast freights, only for slower drag freights (like iron ore); because of their counterweights, etc. they had a speed limit of I think 35 MPH. The story is from one of Frank King's books if I recall correctly, he was a VP of the Missabe and was would have been there when it happened.