To be honest with you, I don't know. The only thing that I can attribute it to is many wrecks and rebuilds, although that can't be the only reason.
Perhaps a few were experimented with to improve adhesion.
As Mike Trent pointed out, the South Park was always trying to tweak their locomotives to see if they could get more tractive effort out of them. Perhaps the heavier Cookes were an experiment that either didn't work out or was stopped because heavier power came on the property. I have no idea.
Don't worry John, I always find time for the fun stuff. Wait... I'm retired... it's all fun stuff now. In answer to your question. No, I haven't put the maps that you mentioned into electronic form yet. Just wait and I'll get to it. If I live long enough and you don't put me in a (pine) box....
I'd be curious as to the exact reason main rods were changed out - I'd venture to say it changed the torque to revolution ratio as it does in a gasoline engine - longer stroke different torque (Mopar 340 as opposed to 360 cubic inch for example - also changed displacement). But not knowing I'll defer to the Master (who thinks I talk too much, anyway).
I do know this; main rods changed back and forth from short to long and long to short - back again - in what appears to be at random - during the early years (1st Decade) when the RR was tweaking the tweaks! Testimony to their effort to wring every drop of efficiency out of the available motive power. Take a look at 69 for instance... Check out 44. Any engine with lots of copy. Why?
To be honest, I don't think that the pair of longer main rod would add that much overall weight to a locomotive. I know that they had to be heavy, but compared to the Main and Side rods that I was used to, those on a C-19 or 3' gauge locomotive remind me of wrenches.
As I said, I don't really know why there was the big weight differential. Another mystery for someone to solve...
I can't see how the longer Mainrod would be any different powerwise from the shorter version ie third driver vs second driver as the piston stroke doesn't change. The shorter rod would be stronger too.
Below are the differences I found (for Narrow Gauge only) between the Loco Roster you posted in the files section (did this come from Valuations or from other records?) and those records which list AFEs for disposal.
"Unit Record of Property Changes - Equipment"
Account No. 51 - Steam Locomotives
C&S No. 4 shows dismantled (AFE 9484) May 1934.
C&S No. 5 shows dismantled (AFE 10264) Dec. 1938.
C&S No. 6 shows dismantled (AFE 10264) Dec. 1938.
C&S No. 7 shows dismantled (AFE 8071) Sept. 1929.
C&S No. 8 shows dismantled (AFE 10264) Dec. 1938.
C&S No. 9 update - currently display in Breckenridge (OOS -AFE 10548 Dec. 1940)
C&S No. 10 shows dismantled (AFE 9484) May 1934.
C&S No. 13 dismantled (AFE 5017) Aug. 1923.
C&S No. 21 dismantled (AFE 5018) Aug. 1923.
C&S No. 22 dismantled (AFE 6655) Mar. 1927.
C&S No. 30 Traded to Morris Bro. (AFE 3918) Feb. 1921.
C&S No. 37 dismantled (AFE 4300) Dec. 1921.
C&S No. 40 Traded to Morris Bro. (AFE 3918) Feb. 1921.
C&S No. 42 Traded to Morris Bro. (AFE 3918) Feb. 1921.
C&S No. 43 Traded to Morris Bro. (AFE 3918) Feb. 1921.
C&S No. 49 Traded to Morris Bro. (AFE 3918) Feb. 1921.
C&S No. 55 Sold to CM&St.P (AFE 2780) July 1918.
C&S No. 58 dismantled (AFE 10264) Dec. 1938.
C&S No. 59 dismantled (AFE 6655) Mar. 1927.
C&S No. 65 dismantled (AFE 10264) Dec. 1938.
C&S No. 66 dismantled (AFE 5053) Sept. 1923.
C&S No. 67 dismantled (AFE 6548) Feb. 1927.
C&S No. 68 dismantled (AFE 10264) Dec. 1938.
C&S No. 69 NR - assumed Sold to Morris Bro. (AFE 10712) Dec. 1942. (WP&Y)
C&S No. 70 NR - assumed Sold to Morris Bro. (AFE 10712) Dec. 1942. (WP&Y)
C&S No. 71 NR - assumed scrapped (AFE 10539) May 1941.
C&S No. 72 NR - assumed scrapped (AFE 10467) Oct. 1940.
C&S No. 73 NR - assumed scrapped (AFE 10467) Oct. 1940.
C&S No. 74 NR - assumed Sold to Morris Bro. (AFE 10803) Aug. 1943. (RGS 74)
C&S No. 75 NR - assumed Sold to Morris Bro. (AFE 10803) Aug. 1943. (S.A.?)
C&S No. 76 NR - assumed Sold to Morris Bro. (AFE 10803) Aug. 1943. (S.A.?)
No dispersions on Ricks roster implied and actually there may be further records that support the mere months differences since it may have been some time between actual disposal and the issue of an AFE. Thanks Rick.
The question continues about what No.s 37 - 39 were (Baldwin or Cooke). The above document indicates both 37 & 55 were built by Cooke Locomotive Works and both had 37" drivers. According to the above URoPC as well as the C&S Folio Sheets engine 30 was built by Baldwin. It had 37" driver. No.s 37 - 56 were built by Cooke. Both the URoPC and C&S Folio Sheets indicate they had 37" Drivers. No. 30 was classed as B-4A by the Railroad - the only B-4 A loco in existence in June 1906 when this classification was devised. Engines 37 to 56 were all classed as B-4B. The records indicate 20, 2-8-0 Cooke Locomotive Works engines delivered to the DSP&P in 1883 - the URoPC says 1884 - go figure. The question then is how many Baldwin engines were actually delivered and how many Cooke engines were actually delivered. There are no breaks in the original DSP&P numbers so they translate all units to the C&S. However DSP&P no.s 41 - 49 which translate into C&S 37 - 45 are separated from the rest of the Cooke engines by 8 Baldwin engines, DSP&P 50 - 57. The C&S disposed of all of the Baldwins except No. 30 (DSP&P 50) before 1902. But they didn't dispose of 37 - 45 (3 of which seem to stand in this dispute). My conclusion is that there were 8 Baldwin and 20 Cooke 2-8-0s. I'd guess the Loco Roster Rick posted was directly from a Valuation Document. AFE means Authorization For Expenditure.
The URoPC does not indicate where an engine may have wound up - only what the Railroad did with the engine. They Sold 74 to Morris Brothers but had nothing to do with the RGS purchase of that engine (I've indicated that after the document's details). Often there is no description of what happened to the engine. This is indicated by a NR (no record). You will also note that AFEs are often listed for more than one engine. AFE 3918 clearly authorized the disposal of 30, 40, 42, 43, 45 in trade for 74, 75, 76 in Feb. 1921 and then 74, 75, 76 were disposed of by AFE 10803...
To my knowledge, the main rods were never "lengthened" at all on a locomotive that was not engineered from the
from the builder to have them. The B-4-E's were built that way, so were the B-4-F's and #537.
This was part of the evolution of the steam locomotive through the 1890's as larger and heavier locomotives were built.
I seriously doubt you will ever find photos that show the same locomotive connected to the third axle in one photograph and to the second axle in another.
Sorry if my comment led anyone to that conclusuon.
I'm glad to see that somebody's looking at this stuff.
The Locomotive Roster is a distillation from various sources. Some Rosters done by others, mostly from the Valuation, Comparison with Folio Sheets, Employee Timetables, wherever I could find reliable information.
Like I said, I have no idea why some were heavier than others. Could have been C&S's doing, but in my opinion (and ONLY opinion as I have no real facts to back it up), more than likely UP's, as they were trying to wring out as much tonnage as they could out of each Locomotive. Remember, the UP was in financial trouble and they were piecemealing their locomotives together to haul as much as each could. This is for the same reason that it is done today. Fewer Crews plus more tonnage equals more profit.
Just as a side note, when I used to catch trains out of Denver going north to Laramie and Rawlins out of UP's Hill Yard (Now Coors Field), there was a track that went around the perimeter of the yard, and there was a sign next to one of the turnouts that said "Morse Brothers Machinery". Maybe one of these days I'll do a graphic reconstruction of that yard, but not today....
Well, Mike then I don't know how to explain the two photos on page 376 of "the "Pictorial Supplement to the DSP&P". And I don't know what to say about the photo of what would become 69 on the Turntable at Como (272) on page 354 to that of 69 (upper left) page 381 - same volume. These are just a couple of examples. (I try very hard not to just pull things out of my arshe....)