Hi,
I'm just wondering how prototypes manage to keep a caustic load in a car to no contaminate a later load. For instance, if a car handles a chemical for one load then in another shipment handles grain. How is this all done?
Cars used in food service are designated for food service, and would never be used for a non-food load, caustic or not. In fact, they're most often designated to their specific kind of food load -- a grain hopper would likely not be used later for sugar or flour, for instance. Likewise, tank cars that carry corn syrup would almost always carry just one particular grade of corn syrup, never chemicals. This makes assigning cars to industries more complicated, but for modelers, more fun.
--Steven Otte, Model Railroader senior associate editorsotte@kalmbach.com
In addition to the information Steven supplied, cars that are consigned to a shipper are expected to return to the owner in clean condition with dunnage, strapping and other debris removed otherwise the shipper is charged for cleaning this stuff out.
Same thing would happen to you if you return a rental car full of trash.
A freight agent may be able to find a shipper needing the same type of car for a return load so the empty car is routed to that shipper, otherwise, there might be return instructions and routing stenciled on the outside of the car such as "When empty return to B&O Railroad, Chicago, via best route".
Bigger terminals would have designated areas for car cleanout. Tank cars are frequently owned by the shipper so the commodity is usually the same and the empty car returns to the origination point empty at a reduced rate. The car still has to have a plackard showing what the last load was but would be noted as "empty" since the fumes can still pose a hazard. Sometimes tank cars are cleaned by special crews wearing protective gear. It can be very hazardous, though. Occasionally, there are accidents where confined space protocalls are not followed.
Enjoy The Hobby, Ed
Welcome to the forums.
I think your question has been pretty well answered above. However, even the best intentions can go wrong.
A number of years ago, when I was a volunteer fireman, one of our Hazmat classes included a box car fire. None of the contents of the load were hazardous, nor were any of the recent previous loads. Investigation finally found that one of the products in the current load and some product from a recent load had spilled. As I remember one was a liquid. Though neither product was flammable, when combined, they created a flammable product that had started the fire.
Good reason to be careful of what you carry and handling it safely.
Have fun,
Richard
Thanks everyone. This all makes sense... And it keeps things interesting! Cheers
That's one reason many cars used for a specific product / industry are privately owned, rather than railroad owned. You'll notice most tank cars, refrigerator cars, and many covered hoppers have reporting marks ending in "X". This indicates the car is privately owned, or is leased to a private company. The company then can control what goes into the car, so their corn syrup tank car doesn't get used for hauling caustic soda or petroleum.
Short answer, the shippers or railroads clean the cars between loads. Normally chemicals are kept ithe same cars. Cars are designed for particular commodities with specific sizes to hold the the maximum quantity of commodity based on the density of the material. That's why acid tank cars are smaller than LPG tank cars. The cars also will have different linings suited specifically for specific commodities. A car carrying caustic soda will most likely have a different lining than a car carrying acid or alcohol or corn syrup.
And it doesn't have to be food or chemicals. There was a shipment of iron ore from Minnesota to a steel mill in Utah to a coal mine in Utah, then loads of coal to a power plant back in the midwest, then empties to the iron ore mine all in conventional triple or quad open top, bottom dump hoppers. The ore was shipped as taconite and the cars had to be cleaned after the ore was emptied, before the coal was loaded.
Why? Coal going to a power plant is crushed to a fine powder and blown into the firebox of the boilers. A set of rollers crush the coal. It a taconite pellet get into the coal, when the pellet goes through the rollers is separates them enough that some of the coal is not crushed and so doesn't blow properly into the boilers, reducing their efficiency. There is also the outside chance that the iron ore bouncing around in there could cause a spark and a confined area filled with powdered coal is not a place you want sparks.
Dave H. Painted side goes up. My website : wnbranch.com
Steven Otte Cars used in food service are designated for food service, and would never be used for a non-food load, caustic or not. In fact, they're most often designated to their specific kind of food load -- a grain hopper would likely not be used later for sugar or flour, for instance. Likewise, tank cars that carry corn syrup would almost always carry just one particular grade of corn syrup, never chemicals. This makes assigning cars to industries more complicated, but for modelers, more fun.
Wasn't there an article about dispatchers in last months "Trains" article where one of the dispatchers interviewed accidently routed a hopper that had been carrying rat poison previously to a feed mill and it resulted in a dozen cows dieing as a result?
DavidH66 Steven Otte Cars used in food service are designated for food service, and would never be used for a non-food load, caustic or not. In fact, they're most often designated to their specific kind of food load -- a grain hopper would likely not be used later for sugar or flour, for instance. Likewise, tank cars that carry corn syrup would almost always carry just one particular grade of corn syrup, never chemicals. This makes assigning cars to industries more complicated, but for modelers, more fun. Wasn't there an article about dispatchers in last months "Trains" article where one of the dispatchers interviewed accidently routed a hopper that had been carrying rat poison previously to a feed mill and it resulted in a dozen cows dieing as a result?
yes
And speaking of dead cows, just about the ultimate in single-purpose cars were the boxcars downgraded to hide service. I don't think there was anything lower than hide service that a car could be downgraded to. The last single sheathed wood boxcars I recall seeing in regular service delivered untanned and uncured hides to a local tannery in my town right up to when I left for college in 1970. They were invariably marked for Hide Service Only. I always wondered: if the car was loaded with hides right up to its maximum capacity, did the flies and maggots add appreciably to the weight?
But even hide service was not the worst possible load. Bits of hide (or bone) that still had tidbits of meat stuck to them were cut away and were sent by truck or, evidently, gondola to glue factories, fertilizer plants, and animal feed (probably chicken feed) plants and were classified or called "fleshings." I believe both tanneries and slaughter houses shipped fleshings.
But it got worse. The slaughter houses in addition to fleshings also shipped animal offal again to fertilizer or glue factories, in open gondolas. I recall seeing such gondolas in Oak Creek WI at the depot there. What an odor on a hot day (or cold day for that matter). And the flies were just amazing. The C&NW crews called them "gut cars." Now and then the gasses would build up or a gut car was hit hard upon coupling and some of the load would slosh over. I was told that when ties needed to be replaced at Oak Creek the ground was so permeated with "material" from gut cars and lifting the old tie out of the ground would release all the odors all over again, and the ground was actually spongy when shoveled.
I don't know if the gondolas that served as gut cars were single purpose or whether it was some poor guy's job to clean them out for the next load of pipe or scrap metal or whatever. I did talk to a guy whose job it was to clean out tank cars that were in dedicated "inedible tallow" and "edible tallow" service at a local slaughter house (Patrick Cudahy). He said guys could and did actually die doing that and there was usually a two man crew, one up above outside to monitor the condition of the low guy on the totem pole who had to go inside the tank car.
Dave Nelson
Thank You.
Often the cleaning of tank cars is subcontracted, for example. An interesting industry here in Fort wayne, Indiana was an outfit that used the tracks, turntable and the old Wabash roundhouse below the elevation in the 1970s and 1980s to clean tank cars. Also, I don't know where she worked, but my sister-in-law, during her college days, had a summer job cleaning tank cars. IIRC, she had to wear protective gear, a suit, rubber boots, etc. and climb into the tank cars. I believe she said that there were two assigned to the cars and they used the "buddy system". She is from the Hammond-Whiting, Indiana area. I forgot the details as to who she worked for, though I recall her father worked for Lever Brothers, so that might be a clue. Perhaps some day soon I'll ask for more details. And I thought I had some unusual summer jobs...