Western Railroad Discussion > tank car unit train question

Hello all. I'm was a railfan as kid in the 80s. For over the last year I have worked in Atchison KS and my office is near the UP line and that has kind of rekindled my interest. Anyway a UP unit tank train just passed with one hopper on each end. First time Ive notice this on the UP but I have noticed it on the BNSF line in Mo a few miles away a lot. I know there must be a reason for the single hopper on each end. These are tank car trains but I have no idea what it is hauling. What would be the reason for the covered hopper on each end?

Shield the crew from the explosion.

Out

To elaborate, the hopper on each end is a "buffer car" intended to establish some separation between the locomotives and the train in the event of a derailment or collision that could cause a leak/spill/rupture of the cargo, which is either crude oil or ethanol depending on the train. (There are other types of unit tank-car trains, but some do not haul materials for which buffers are required and oil and ethanol are now the predominant cargoes for those that do.)

A single car minimally complies with operating rules/regulations providing for such a buffer. I believe that up to six buffer cars are required "if available" under at least some railroads' rules (if not federal regulation) but "availability" apparently is subject to interpretation.



Edited 1 time(s). Last edit at 10/23/14 14:38 by toledopatch.

I honestly do not see the point of buffer cars on unit trains, if a derailment or crash is so severe that a fire or explosion occurs, the train crew and locomotive are screwed anyway.

Posted from Android

trkspd Wrote:
-------------------------------------------------------
> I honestly do not see the point of buffer cars on
> unit trains, if a derailment or crash is so severe
> that a fire or explosion occurs, the train crew
> and locomotive are screwed anyway.
>
> Posted from Android


You have that right!! doug

trkspd Wrote:
-------------------------------------------------------
> I honestly do not see the point of buffer cars on
> unit trains, if a derailment or crash is so severe
> that a fire or explosion occurs, the train crew
> and locomotive are screwed anyway.

It does provide a little "crush" zone if you have a head-on or rear-ender.

The regulation was set at a 5 car buffer and is still in effect. There is an exemption for trains which do not have enough inert cars to provide a buffer of this length. So a buffer of 4, 3, 2, 1 or ever no cars would be allowed. When 50+ volatile cars were run in unit train configuration the FRA decided there should be at least one car separating the power from the volatiles.

When the MRL gets a unit oil train at Laurel there is one buffer on each end with head end locomotives and a DPU. Laurel Yard switches in two empty cars of any type into the middle of the train. Later helpers will be cut between these mid train buffers to shove the train over Bozeman and Mullan Passes. The mid train buffers are switched out at Missoula.

Posted from Windows Phone OS 7

As further information on the topic, both BNSF and CP have dedicated buffer-service cars. BNSF has taken old Airslide hoppers and assigned them as buffers, with new car numbers and stencils, while CP uses old grain hoppers for the purpose. Both railroads have loaded the cars involved with sand.

And when some asks, and they will, the cars are loaded with sand because that is a material that have very little value in itself. If need be, that car can later be shipped to a customer and another load of sand replaces it. Cars of other material are sometimes used if they are 'storage cars' and the contents are not sold yet.
Shielded from the explosion, rarely. Shielded from the leaking and flammable material for a little while to escape, yes. Gives you another 55 feet of distance I would certainly take it. And that's only if it is the lead car that leaks.

UP uses empty hoppers that are modified for buffer service with the gates removed. I've used MOW open top dump cars before too.

Posted from Android

An empty at the front of a loaded train? Isn't that a problem?

One would think but I've had them billed as empty? Maybe the hopper gates were welded shut? Heck I don't remember .... Its been a long time since I built a unit train. Sorry. What I am trying to say is, maybe I remembered that one wrong.
Posted from Android



Edited 1 time(s). Last edit at 10/23/14 20:13 by trkspd.

Also, a note for any fellow train crew guys out there. If your DPU is removed or moved to the head end that buffer must also go to the head end. We have to use all available buffer cars, the one on the rear is not serving any purpose when that DP is removed and the train is out of compliance. We've had a crew get in trouble for it before.

PHall Wrote:
-------------------------------------------------------
> An empty at the front of a loaded train? Isn't
> that a problem?


Only if it's over 5500 trailing tons. Most unit trains are. The BNSF has sand in thiers I believe but are billed empty. No revenue. But they show loaded on the wheel whatever they weigh. Usually around 80-100 tons on the ones I have seen. And they are welded to prevent draining the load out of them.

A few weeks ago, I saw a train that picked up 7 flatcar container loads of explosives from the military. They used 6 buffer cars (hoppers) plus a shoving platform between the power and the flatcar loads.

gary

From what I understand, the buffercar's main purpose is to keep the engines separated from the tankcars if an engine were to catch on fire, to keep the tankcars from igniting from that engine fire.

While buffercars may slightly help the crews if the tankcars were to derail and/or explode, I don't think that's its main purpose.

B_Perkins Wrote:
-------------------------------------------------------
> Also, a note for any fellow train crew guys out
> there. If your DPU is removed or moved to the head
> end that buffer must also go to the head end. We
> have to use all available buffer cars, the one on
> the rear is not serving any purpose when that DP
> is removed and the train is out of compliance.
> We've had a crew get in trouble for it before.


Hm. I've seen plenty of these trains in the East without DPUs and yet the buffers are front-and-rear - one at each end. Another TOer frequently reports adding a rear buffer to trains that don't already have them because the trains will pick up helpers later in their journeys.

I watched one yesterday on the Rochelle cam (BNSF) with a buffer on each end.

Solid unit trains of hazardous materials be it loaded or empty must have a buffer at the head end and rear end.

As far as the buffer on the head end being empty, you'll never find a RR stupid enough to do that, especially once the train is loaded and has 15,000 tons of force behind it, you'll derail that thing in a heartbeat!!!

Posted from Android

Poker's response is pretty much right on, separate the locomotive fuel from any flame in
the load area. Interestingly you don't see the use of buffers on local spots of LPG, which
has a blast radius of a 1/4 mile.

Out