hopper size?

Discussion in 'The Real Thing- North America' started by ozzy, Jan 28, 2008.

  1. ozzy

    ozzy Active Member

    what is the reason for the different hopper sizes? 2,3 and 4 bay hoppers? is it just that the cars got bigger when the trains/power got bigger? why would they use a 2 bay hopper when a 4 bay can hold twice as much?

    and are there anything besides grain carried in them?
  2. puddlejumper

    puddlejumper Member

    Improvements in metallurgy and bearings (as related to the max load of journal bearings). As technology improved, capacities increased.

    Open hoppers carry anything not weather sensitive. Coal, sand, rocks, ballast, etc. Closed hoppers carry weather sensitive commodities. Grain, concrete, dry sand (such as locomotive sand), animal feeds, corn, pellets, etc.
  3. who_dat73

    who_dat73 Member

    Dont they usally carry sand and heavyr stuff in the two bays so as not to overload the hopper or rails I think somone told me that once????
  4. nkp174

    nkp174 Active Member

    The two bay hoppers were typically 55-tons. As Puddlejumper said, the technology (& economics) improved and the cars got bigger.

    The other aspect was the $$$ of labor versus material. Truss bridges were common when material was expensive & labor cheap...this was reversed in the US after WW1. This affected everything that required labor & material.

    2-bay steel hoppers date from before WW1. 3-bay hoppers date from the 1930's onwards. 4-bays...iirc...began after ww2...but 2-bays were still the primary hopper cars into the 1950's.

    For a similar example of car tonnage growth...in the 1870's, the DSP&P had mostly 8-10ton cars. In 1880, the switched to 12-14ton cars. In 1884, they took deliver of 20 ton cars. So a doubling in size in only 5 years. Correspondingly, the locomotives became substantially larger/more powerful. The easiest way to guess the weight of a car...aside from reading the capacity off of the side...is/was to look at the trucks.
  5. puddlejumper

    puddlejumper Member

    I do believe that nowadays they do make some 100 ton 2-bay cars. It is true that extremely dense commodities will usually be found in two bay cars such as sand and concrete. You will notice that Iron Ore is usually found in little 20 foot cars with one bay or in partially loaded hoppers because that material is so dense.
  6. nkp174

    nkp174 Active Member

    Excellent examples! The more material it takes to build a car, the more the car weighs and the less it can carry (it also costs more to build). For my railroad, the platform cars (flats, gondolas) had higher capacity ratings than the house cars (boxes, stock, reefers).

    Another example of this...which is easy for me to comment on...is the weight of a Nickel Plate R-22 tender (the tenders behind the berkshires & the 587...and the C&O Kanahawas and the PM 1225 IIRC). Full the tender weighs 361,700lb. 44,000lb of coal, 183,000lb of water, and 132,700lb of dead weight...more than a third of the weight is dead weight!

    You want to use the smallest car possible to ship your load since it will minimize the dead weight you have to carry (and the cost of the cars). Railroads don't measure freight moved by cars or volume...they measure it by ton-miles. Less deadweight means more ton-miles per locomotive.
  7. ozzy

    ozzy Active Member

    i would think that 2 , 2 bay cars would cost more to make/buy/ upkeep then 1 4 bay car?..........

    if you have 2 two bay cars you have to buy and maintain twice as many wheels/trucks, and couplers. and twice as many "end sides" meaning that much more steel is needed.

    the 4 bay you still only have 2 trucks and 2 couplers ands only 2 end sides. but can still hold the same as 2 two bays.

    with all the extra trucks and couplers that just adds to the cost of man power to keep them in good shape,

    thats just the way i look at it anyway.
  8. puddlejumper

    puddlejumper Member

    But for really dense commodities you can't fill a 4 bay car to it's capacity in cubic feet. The car will be at its weight capacity but only be 1/3 or 1/2 full. So you still need the same amount of cars as you would if you used 2 bay cars filled to the top.

    A 20 foot ore car carries 100 tons, put that same load into a 100 ton 4 bay hopper and it barely fills the inside of the hoppers.

    Make sense?

  9. ozzy

    ozzy Active Member

    i guess i have never known anything but grain or beans to be carried in hoppers,

    Attached Files:

  10. Triplex

    Triplex Active Member

    Most people would automatically assume an open hopper (for coal, ore, etc) when the word "hopper" is mentioned. I see you were assuming a covered hopper (for grain, sand, etc).

Share This Page