snip: If both gave the same increase in efficiency, why not do both and "double" the total increase?
reply: Because then they would have been French. ;~>.
Serious replies:
1) The French designed and built hundreds of superheated compounds (and the Germans superheated many of theirs). While they might have preferred the US-built 2-8-2s after World War II, that reflected changes in how they crewed their engines.
2) I recall reading several contemporary commentaries that pointed to the excessive condensation in the LP cylinders because of lower-pressure steam being admitted into a larger volume. Superheat would have reduced this, but very few North American engines went that route. The N & W 2-8-8-2s (and the USRA derivatives) are noble exceptions.
JimValle Compounding went out of use when superheaters were introduced around 1910. They offered the same increase in efficiency without the maintenance nightmares.
Compounding went out of use when superheaters were introduced around 1910. They offered the same increase in efficiency without the maintenance nightmares.
If both gave the same increase in efficiency, why not do both and "double" the total increase?
There's also at least one other type of Compound: the tandem. With everything out in the open, it seems like it should have been more successful.
Ed
Actually four cylinders was the norm for compound engines in 1904. The Vauclain Compounds featured a high pressure and a low pressure cylinder stacked one on top of the other on each side of the locomotive with the valve cylinder inside. The Balanced Compounds had the high pressure cylinders inside of the low pressure cylinders but still one of each on each side of the locomotive. Only the Cross Compounds had two cylinders, a high pressure cylinder on one side feeding steam into a low pressure cylinder on the other side. Although it was theoretically possible to equalize the work output of the high and low pressure cylinders by applying Boyle's Law to determine the dimensions of the pistons and cylinders, in fact it was very difficult to get the system "square". The high pressure cylinder almost always did more work which resulted in uneven wear on the crosshead guides or wracking of the engine frame on Cross Compounds. Compounding went out of use when superheaters were introduced around 1910. They offered the same increase in efficiency without the maintenance nightmares.
As far as compound mikes go, the D&RG narrow gauge class K27 built in 1903 accounted for fifteen of the thirty in this table. This was the glory time of compounding, but most didn't last long in that configuration. Yes, they did save on coal and water, but the maintenance costs and added complexity more than made up for the savings in fuel. The one exception to the early demise of compounding was the true mallet type, of course. Many of these were very successful engines with many lasting through the end of steam.
Thanks for the data. It was very interesting.
I had known that Consolidations outnumbered all other types but didn't think they did that early. I was also a bit surprised at the number of different types at that early date. I opened this thread expecting to see 4-4-0s in the huge majority and a handful of other types.
Another example of the greatest thing about ferroequinology: You just can't avoid learning something knew every day, regardless of how long you've been studying the beast.
ChuckAllen, TX
I really enjoyed seeing this chart.
The Ten-Wheelers are at #3 at the moment, but as they say in the music biz they were #1 With A Bullet. At least in the CPR's case, they were the largest single type of steam locomotive they owned when it was all said and done. In fact it accounted for 40-50% of all the steam engines the CPR owned.
And it is interesting to see the start of the Pacific and Mikado's rise to dominance in the industry.
Thanks for posting this.
Bruce
So shovel the coal, let this rattler roll.
"A Train is a Place Going Somewhere" CP Rail Public Timetable
"O. S. Irricana"
. . . __ . ______
gbrewer Ed, A very interesting chart indeed.It gives on a good prospective on locomotives in one year in the real Railroad Glory Days. Yes, those non-articulateds compound enjoyed a considerable if very brief popularity.
Ed,
A very interesting chart indeed.It gives on a good prospective on locomotives in one year in the real Railroad Glory Days.
Yes, those non-articulateds compound enjoyed a considerable if very brief popularity.
Which reminds me: The D&H 4-8-0 triple compound of 1933--I wonder how successful it was AFTER correcting for the possible/probable lack of support from the folks who actually took care of it after it was "out on the line".
As I recall, there are a couple more equally interesting charts buried in that book. Glen Brewer RailroadGloryDays.com
As I recall, there are a couple more equally interesting charts buried in that book.
Glen Brewer
RailroadGloryDays.com
Oh, yes. And much, much more.
Below is a modified version of my response in another part of the forums. Thought the folks here might be interested if they hadn't seen it earlier. Particularly striking to me is the quantity of compound locomotives:
Wow, what are the odds? I just ambled in to look at one of my all-time favorite steam locomotive book (Alfred W. Bruce's "The Steam Locomotive in America") and the pages just about fell open to page 71. Thereon is a chart which may not be a total answer to your question, but it'll help. It's titled "Types of main line steam locomotives in the United States as shown in the Consist of December 31, 1904". Bruce also says about this chart "...presents the motive power consist at the end of 1904 on the United States railroads reporting to the Interstate Commerce Commission."
Numbers after the locomotive type are the total (if I added correctly) of the other numbers of the row.
2-8-0 11399 765 4 cyl comp 376 2 cyl comp 10258 simple
4-4-0 11323 60 5 11258
4-6-0 9232 502 280 8450
2-6-0 5465 148 149 5168
0-6-0 4764 2 30 4732
0-4-0 1172 1172
4-4-2 852 159 693
4-8-0 557 64 493
2-6-2 456 179 26 260
4-6-2 233 85 148
0-8-0 168 168
2-4-2 121 20 101
2-4-0 51 51
2-8-2 34 31 3
2-10-0 15 10 5
0-10-0 10 10
misc tank 256
Gee, a 4 cylinder compound 0-6-0. Who knew? Not shown is B&O's 0-6-6-0--(built in 1904???)--perhaps it hadn't been officially accepted yet? And 4-cylinder Mikes outnumbering simples? Maybe, maybe not.
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