Hi
I got a question for the experts on Steam locomotives, how are the weights for the drive wheels determined. Thank you in advance, Pat

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Remember one weight - and one weight only would be applied to the entire class of locomotive being constructed - within that class weights could legitmately vary by several humdred pounds.

I have a copy of the correspondence between the AT&SF engineer dept. and Baldwin Locomotive Works on the Weight on Drivers for there 5011 class 2-10-4 . After BLW weighted the first 3 locomotives the average weight of drivers did not meet the minimum specified contractual weight. AT&SF engineer dept. Longhand worked out the moments using the measured actual average weight per driver minus the unspring weights of driver wheels sets, boxes, saddles, springs and rods. Then they calculated the changes of equalizer lengths and frame positions to remove weights from lead and trailer truck to bring weight on drivers to contractual specification. Being that the war was on and the AT&SF need locomotives the first 3 were shipped to Topeka Shops for the work to be accomplished. BLW made the changes on the rest of the order. This correspondence is one of the best examples on how to adjust locomotive axle weights.
If anyone would like a copy PM me with your email.

Dennis Daugherty

On a related note, I found this interesting caption in a book about the NYO&W regarding weight on drivers vs. requirements to equip with a stoker:

This is from the book "The Final Years - New York, Ontario & Western Railway" by Carstens Publications. Admittedly this is a "railfan" book, and not original archival material, so without doing some digging I don't know just how accurate the weight vs. stoker comment is, but interesting to ponder nonetheless.

-Erich Armpriester
Strasburg Rail Road Mechanical Services

I have a number of pages of notes associated with weights and equalization of the War Department S-160 Consolidations. It appears that the weight of every item, down to .01 pounds for cotter pins, was estimated as part of process and each part's location on the locomotive was determined to establish the center of gravity. On one worksheet an early locomotive of the design was weighed incomplete with sandbags or estimates were made for missing parts. One worksheet included the note:

Condition of loco at time of weighing 8/3/42
200# pressure
2 gauges water
2 men in cab
6" fire on grate
1000# sand (equiv. wt. on running board)
600# firebrick (equiv. wt. on running board)
Individual scale 160370
Platform " 160300
Difference 70

In correspondence in the early 1950s the Alaska Railroad responded to a request from the union to add stokers to the S-160s. The weight didn't meet the threshold and the request was denied.

Your post is ridiculous. A separate scale for each axle? The scale could then be used for one wheel arrangement and diameter. It was weighed one axle at a time just as trucks are weighed today. One scale required.

One should do scholarly research before declaring rubber tired technology of 2021 applied to steel tired unbalanced reciprocating technology of the last century.

Reminds me of a conversation I had with a Radio Shack clerk once that told me he could program computers. I asked, "What language? FORTRAN, PL1, C++,....." He said, " It's easy, you just put the CD into the slot....."

There is an existing scale building at Spencer Shops that I saw on a tour of the complex during a joint ARM and TRAIN annual conference in November of 2001. Let me try to explain it.

As I recall the track in the building is above a pit that extends to each side. The track is made up of multiple sections with each section acting as part of a separate scale. The locomotive would be moved into the building and once positioned the sections of the track beneath each axle would be released and the weighting would be done. There may be other sections that would not be used. Each section of the track is connected to an oversize mechanism like that used for platform beam scales. Think of this being done by multiple short versions of traditional track scales for weighing freight cars. Thus the weight carried by each axle would be measured and the entire weight measured at the same time. There is no chance of weight transfer that may occur if weighing each axle separately.

Remember this was long before transducers that measure stress and force were developed.

Baldwin Locomotive Works scales, https://www.alamy.com/american-engineer-and-railroad-journal-de-glehn-ten-years-agoand-now-running-in-continental-europe-the-same-prin-ciples-are-embodied-in-the-engines-of-the-nord-railway-in-aletter-to-mr-rons-marten-published-in-the-engineer-mrde-glehn-gives-his-reasons-for-designing-this-type-which-maybe-summarized-as-follows-this-type-was-selected-chiefly-because-of-the-limit-imposedupon-the-weight-the-compound-type-uses-steam-more-eco-scales-for-weighing-locomotivesbaldwin-locomotive-works-although-rigid-restrictions-are-placed-upon-the-weights-oflocomotives-upon-their-driving-wheels-and-the-image375041476.html?pv=1&stamp=2&imageid=65D9D916-D2D0-4E80-99CA-3E21BEA9D692&p=1331751&n=0&orientation=0&pn=1&searchtype=0&IsFromSearch=1&srch=foo%3dbar%26st%3d0%26pn%3d1%26ps%3d100%26sortby%3d2%26resultview%3dsortbyPopular%26npgs%3d0%26qt%3drailway%2520weighing%2520scales%26qt_raw%3drailway%2520weighing%2520scales%26lic%3d3%26mr%3d0%26pr%3d0%26ot%3d0%26creative%3d%26ag%3d0%26hc%3d0%26pc%3d%26blackwhite%3d%26cutout%3d%26tbar%3d1%26et%3d0x000000000000000000000%26vp%3d0%26loc%3d0%26imgt%3d0%26dtfr%3d%26dtto%3d%26size%3d0xFF%26archive%3d1%26groupid%3d%26pseudoid%3d%26a%3d%26cdid%3d%26cdsrt%3d%26name%3d%26qn%3d%26apalib%3d%26apalic%3d%26lightbox%3d%26gname%3d%26gtype%3d%26xstx%3d0%26simid%3d%26saveQry%3d%26editorial%3d1%26nu%3d%26t%3d%26edoptin%3d%26customgeoip%3d%26cap%3d1%26cbstore%3d1%26vd%3d0%26lb%3d%26fi%3d2%26edrf%3d%26ispremium%3d1%26flip%3d0%26pl%3d

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Find a copy of Huddleston and Dixon's "The Allegheny, Lima's Finest". Pages 66 and 67. Photos in Lima's scale house. On page 66 I can see eight beam scales in that photo. You can also see, as shown in Kelly's post showing the Baldwin spec. page, that the nearest rail has the field-side of the rail head machined away to nearly the web. The scales are clearly built in such a way that they can be individually moved to account for any wheel arrangement they may encounter.

Kent

It is interesting to see what direction the answers to this question went. The first time I read the OP's question I took it as: How do you determine the weights on the drivers for counterballancing? All the answers went the complete opposite direction, and then followed the track of actually weighing the locomotive versus determining what percentage of the locos weight should be on the drivers in the design stage. I reccomend, for the OP, that they attempt to track down a book called The Steam Locomotive. I can't remember the authors name, but he was chief engineer for BLW for a number of years. This book has the answers to almost any question you could ever have about a steam loco.

Edit:
The Steam Locomotive
Ralph P Johnson

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Kelly is quite correct. There were a series of locomotive weight cases taken to the National Board of Adjustment during the 1930s and 1940s. It turns out that many railroads were understating their locomotive weights, which shortchanged the wages paid to operating employees.