Self discharge freight trains

[malc-c]

Back in the late '80s early 90's I worked for BT as an installer in the Luton area. Redland (as it was back then) had a plant in Leagrave and I often took my lunch break parked by the old sidings near the plant. On many occasion I was fortunate enough to watch a train arrive and deliver a load of aggregate, which was fascinating to watch as it was a self discharging train. It swung out a rising conveyor belt over the location where the load was to be deposited, and then engaged a long conveyor belt that ran the length of the train. The contents of the wagons were deposited onto this belt, then on to the rising belt and into the yard.

(image from the internet, not mine)

Does anyone know what happened to these trains as you no longer see them on the network. I watched a 66 deliver aggregate to the Stevenage plant the other month and the train had to be unloaded using a crane with a grab bucket on it which seems a long winded method compared to the old self discharge method.

 

[DarloRich]

ask google and ye shall find: https://assets.publishing.service.g...le/563244/R212016_161027_Barrow_upon_Soar.pdf

...During the maintenance activity a subsequent failure occurred in the control circuit: A push button switch controlling the movement of the unloading wagon conveyor boom became stuck in the ‘on’ position. This caused the boom to fully rotate and, because of the location of the siding in which the maintenance was being undertaken, this placed the end of the boom foul of the nearest of the main lines. There was no instruction to prevent the wagon being maintained on this siding. The risk assessments undertaken in support of the systems of work adopted at the site had not considered the risk of the boom moving out of control and affecting other train operations.

It is probable that the contact block of the push button switch became stuck due to corrosion deposit obstructing its moving parts. This was most likely due to the contact block being exposed to environmental conditions for which it was not designed.
The underlying causes of the accident related to the maintenance of the electrical system of the wagon, and the management of the associated safety risk....

times change

 

[malc-c]

Thanks for the link. So basically due to a combination of poor designed and maintained electrical system, and bad timing that one incident resulted in tarmac mothballing the trains... shame, I still think the concept is fantastic.

 

[AndrewE]

There must be quite a penalty in terms of loss of payload. I can't find any figures, but even if the belts and power supplies aren't very heavy & the payload is similar then the wagons must be a lot longer than simple box or hopper wagons. Isn't train length one of the limiting factors on the loads that can be moved nowadays? It is noticeable how short and stocky the 100T tank wagons are on the continent compared to ours.

 

[GB]

Pretty sure these trains are still used....tho perhaps not as much as they used to be.

 

[Hairy Bear]

All went into storage, post incident at eastfield yard Peterborough.
Have not seen them back in Mountsorrel yard or service since.

 

[61653 HTAFC]

Don't most trains self-discharge (and self-load)?

 

[valentaman]

all sdt wagons met there end at Cf Booth in 2017!

 

[Ploughman]

deleted

 

[DarloRich]

Thanks for the link. So basically due to a combination of poor designed and maintained electrical system, and bad timing that one incident resulted in tarmac mothballing the trains... shame, I still think the concept is fantastic.

I suspect unloading by a grab is quicker

 

[fergusjbend]

I suspect unloading by a grab is quicker

What about the stuff the grabber can't get out (like Alan Bennett's 'little bit of sardine left in the corner of the tin' ). If this has to be removed by a man with a shovel there must be major H&S concerns. Or perhaps the residue is just left in?

 

[kilonewton]

What about the stuff the grabber can't get out (like Alan Bennett's 'little bit of sardine left in the corner of the tin' ). If this has to be removed by a man with a shovel there must be major H&S concerns. Or perhaps the residue is just left in?

A project I worked on had material delivered by train, and unloaded by hi-cab excavators with grab buckets. When estimating our volumes, we assumed a certain wastage factor that the grabs couldn’t get out of the wagons, can’t remember the factor now, but it wasn’t excessive.

 

[AndrewE]

A project I worked on had material delivered by train, and unloaded by hi-cab excavators with grab buckets. When estimating our volumes, we assumed a certain wastage factor that the grabs couldn’t get out of the wagons, can’t remember the factor now, but it wasn’t excessive.

and presumably if the same wagons go to and fro then you only lose it on the first trip (as long as the wagons are weighed in to the loading facility as well as out)

 

[kilonewton]

and presumably if the same wagons go to and fro then you only lose it on the first trip (as long as the wagons are weighed in to the loading facility as well as out)

It was a 2 or 3 trains a week operation, and not every week. The wagons were being used elsewhere, and also there were different types of material being imported, so wastage was wastage as far as that project was concerned.

 

[bishdunster]

How about the H.O.B.C. that visits the Norton Fitzwarren site on the WSR several times a week ?

 

[swt_passenger]

How about the H.O.B.C. that visits the Norton Fitzwarren site on the WSR several times a week ?

AFAICT, it doesn’t include the type of rotatable end conveyor arm that caused the problems. I guess the SDT wagons themselves might have been reusable for something, but perhaps were becoming life expired anyway.

 

[DarloRich]

What about the stuff the grabber can't get out (like Alan Bennett's 'little bit of sardine left in the corner of the tin' ). If this has to be removed by a man with a shovel there must be major H&S concerns. Or perhaps the residue is just left in?

It is honestly next to nowt.

 

[DarloRich]

AFAICT, it doesn’t include the type of rotatable end conveyor arm that caused the problems. I guess the SDT wagons themselves might have been reusable for something, but perhaps were becoming life expired anyway.

They were also short wheel based which is a larger than acceptable derailment risk