# Tank cars spacing behind locomotives



## Pete Chimney (Jan 12, 2008)

I seem to remember that for safety reasons oil or chemical tank cars should not be coupled immediately behind a locomotive. Rather at least one car, e.g. a box car or hopper car, had to be between the tank car and the locomotive. 

This weekend I saw two UP trains along the Hardy Toll Road in Houston, TX with oil tank cars coupled directly to some UP locomotives. Have safety rules been changed?


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## Semper Vaporo (Jan 2, 2008)

Only "hazardous" materials in the tank cars requires the buffer cars... if they were filled with distilled water or honey or corn syrup or some other non-toxic/non-flammable materials, then there is no need for the buffer cars.


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## SD90WLMT (Feb 16, 2010)

Or if they are "empty"...


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## bnsfconductor (Jan 3, 2008)

SD90WLMT said:


> Or if they are "empty"...


Actually Dirk, "MTYS" still require a buffer car depending on the material last hauled. 

The regulations call for 6 buffer cars except for when you can't round up 6... Than it's 5 buffer cars, etc... So with only 1 buffer car the RR's are claiming that 1 car is only available for service. I don't recall the exact language of the FRA, Hazmat & DOT requirements but it's certainly easy to bend the 'rules' to fit the need of the railroad.


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## SD90WLMT (Feb 16, 2010)

Then again....I see tank unit trains with or with out a buffer car....

Buffer cars I do see..almost always are a hopper or a grain car...
..do not recall a box car or sum tin else....
Rule 1. - anything is possible!!
Rule 2. - all else falls under rule 1...


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## Semper Vaporo (Jan 2, 2008)

It can be just about any type of car except a flat or low side gondola. Normally it does not contain any sort of merchandise, but is an old car with some sort of ballast inside to make it similar to the weight of a single car of whatever is in the cars being protected. I regularly see old boxcars when watching the Roanoke (VA) rail cam (Norfolk Southern RR) and the Rochelle (IL) rail cam (U.P. and BNSF RRrs).


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## Pete Chimney (Jan 12, 2008)

These are oil tankers as evidenced by the spill down the side from the central hatch. As they were heading south to Houston, they were probably carrying crude oil down to the refineries along the east side of Houston on the Ship Channel.


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## Pete Chimney (Jan 12, 2008)

This weekend I watched the Rochelle, Illinois webcam hosted through Trains magazine. Several times BNSF trains will all oil tank cars heading east on the BNSF (probably coming from the Williston Basin hauling Bakken crude) passed the webcam and at the end of the train was a pusher locomotive and before this a single coal gondola.

I surmise this gondola was a safety spacer car to keep the oil tank cars from being immediately adjacent to the pusher locomotive. And I believe the rear locomotive is there for extra braking effort, not for use in surmounting any significant grades.


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## Pete Chimney (Jan 12, 2008)

Just caught another train tonight on the Rochelle webcam; a BNSF heading east with a line of oil tank cars, then an empty coal hopper and a single trialing engine bringing up the rear. This may be in response to a series of tank derailments and fires in recent months.


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## ewarhol (Mar 3, 2014)

Pete-

The engine on the rear is known as a DPU (Distributed Power Unit). BNSF has been doing this for years. They are there to help with giving the train a push when starting or climbing up grades. Can't answer about them being used for braking purposes.

When BNSF first started rolling DPU's through my area it was weird to see them. Now it seems weird if a train rolls by and one is not there.


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## Burl (Jan 2, 2008)

Here's a relevant video. Looks like at least two buffer cars:


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## RRwannabe (Jan 20, 2009)

General rule of thumb, loaded haz mat must have 5 buffer cars, empty residue last contained must have at least 1 buffer car. Of course there are exceptions like class 8's (placard hopper cars). The only way a placarded car can ride next to the engine is if on your paper work states the car has been cleaned and purged but that never happens there always residue/last contained cars. Unit trains can get away with 1 because all the cars in the train are hazmat except the one buffer car between the lead power and the DPU, supposedly the FRA allows the 1 rear buffer to remain on a unit train after the DPU is removed.


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## up9018 (Jan 4, 2008)

When you see a string of tanker cars, like something coming from an Ethanol Plant, a lot of times the tank car coupled right behind the locomotive is filled with water to act as a buffer. Sometimes there are even cars strictly dedicted to that task.


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## Jerry Barnes (Jan 2, 2008)

UP sometimes has the DPU in the middle and two on the end.


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## Paul Burch (Jan 2, 2008)

Friday on our way north from Portland Oregon along I 5 we passed a long oil train. One boxcar between the lead locos and the train.


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## vsmith (Jan 2, 2008)

It might have been mentioned already but there is usually always a trailing buffer car at the rear as well.


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