I’ve been watching all the oil trains go thru the “Diamonds” in Rochelle and noticed that all those trains of course are all tank cars but they all have one box car with roof vents either right after the engine consist or at the end of the train. What are those “special” box cars for?
A car containing extinguishers,oil soaking products along with shovels and other tools in case of a leak would make sense to me.Then I may be wrong…
Cars carrying flammable liquids are not allowed next to locomotives. The boxcars, or Airslide covered hoppers, are to separate the oil tank cars from the locomotives. They are called buffer cars. There are no tools or absorbents in them. They are either empty or loaded with something cheap (commonly sand).
Search the forum for buffer car and you will find numerous threads on this topic.
There is nothing special about these cars. It is a regular car that is used to act as a buffer. Federal regulations say that you can’t couple a car carrying hazardous materials directly to a locomotive. I am not sure how they pick cars to be used for this, but I assume they are empty, only weighted down so they don’t derail.
The reason for this is safety. If the locomotive catches on fire, a string of tank cars filled with highly flammable fuel is the last thing you want near that locomotive. In a derailment, a ruptured tank car could spill fuel onto the hot prime mover.
mmm so why does this car appear at the end of the train sometimes?
A buffer for rear end collisions. It acts as a “cushion” to minimize damage to the tankers ahead.
Joe
As noted above, hazmat cars cannot be coupled to locomotives, so if there are DPUs, there needs to be a car at the end. Also, at some unloading terminals, there is no loop, so the back becomes the front when empty. These cars are obsolete in other services, so they are quite cheap.
This is even more evident on some NS trains that will have engines on both ends. No need to run the power around, just have the crew change ends.
From what I have seen both in person and watching the rail cam, you are probably not seeing box cars with vents on the roof, you are seeing covered hoppers.
Those BNSF ‘Buffer’ cars are retired Airslide hoppers that are filled to about 45 tons with either gravel or sand. The DM&E/CP likes to use old covered hoppers or box cars as the ‘buffer’.
The reason for one at each end is due to a couple of possibilities:
DPU engines ‘pushing’
Make switching ends easier
IIRC, the FRA has a directive out that each railroad is resposible for the buffer cars. DM&E has lots of problems with buffer cars being taken for other service, and there was no buffer car for the train when the DM&E went to pick up the returned train. The dedicated BNSF buffer cars fix that problem.
Jim
When loaded, those trains had a DP engine, requiring a buffer on each end. (Buffer car requirements for most loaded hazmat tank cars are 5 when available with a minimum of at least 1 between the cars and engines. Empty cars only require 1 car.) Often when returning the trains are ran conventional, all power on the head end. Since the empty requirement is only for one, they don’t have to switch the second one forward.
Jeff
Out here, in the Great Western Wastes[:-*], 75% of these tank trains have a single locomotive on the tail end. My guess is the car was left in this position, because of this.
Thank you all!
If you ever get close enough to read the “fine print” (i.e. the weight / length etc. lettering), you might see a stencil indicating the covered hopper is “FOR BUFFER SERVICE ONLY” or something similar…at least BNSF cars have it.
p.s. I believe the regulations against running a car with a flammable load right behind the engine goes back to steam days??
Just caught one on NS at CP Wyo the other day, all tank train, except for the covered hopper between the power and the first tank car. I’d expect they are loaded with sand, instead of a light car between the power and the loaded train.
–Randy
If the buffers are loaded with sand its for weight to keep the cars from jackknifing.
I been told by a NS conductor those cars are loaded for added braking and for DPUs or pushers…Also for runaround moves that is required for some customers.
In the recent Trains Citirail video there is a tanker right behind the trailing loco, so I assume it is carrying a nonhazardous load ?
Yes, nonhazardous loads does not require a buffer car behind the engine.
IIRC the 6 car rule between a hazardous load and a occupied car or locomotive is still in effect for general freight train consists.
The hazardous placement rules are Federal law and are the same for every railroad operating in the US. They apply to any train of any type on any railroad, class 1 or shortline.