Title: | Redland Self-Discharge Trains | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Built: | 1988-1990 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Builder: | Standard Wagon, Heywood | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Numbering: | REDA16xxx and REDA92xxx (see text for details) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Running Gear: | Gloucester Pedestal (hoppers) or Sambre et Meuse VNH1 (unloading stations) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Quantity: | 124 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Used: | 1988-c.2016 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Icons: | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Summary: | The Self-Discharge Trains operated by Redland (later lafarge) were an attempt to combine the rapid unloading characteristics of hopper wagons with the operational flexibility of open wagons that required no specialised unloading equipment. This is achieved by use of a conveyor built into the bottom of each set of wagons and an unloading vehicle coupled at one end. Despite the mechanical complexity of the concept it appears to have been successful with several sets built for use both in the UK and abroad. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Profile: |
Hopper wagons have the advantage of relying on gravity for unloading and are therefore not reliant on external equipment such as cranes or grabs for discharge. However, most designs do require fixed infrastructure in the form of under-track chutes or bunkers, and the type is therefore not suitable for short term flows between unequipped locations. Some wagon designs (such as the Marcon bogie gravel hoppers built from 1969) got around this by having the hopper doors higher up, allowing portable conveyors to be positioned underneath. This still required additional equipment though and, depending on the number of conveyors available, unloading could be a slow process.
An experiment in 1982 saw standard PGA hopper wagon PR14329 rebuilt as a so-called 'self-discharge' wagon. The hopper was made up of two compartments, each with a short conveyor belt built into the floor. Powered externally, these discharged the load through an opening in the centre, believed to be on the side above the solebars. Although unsuccessful, the concept was further developed by Standard Wagon, and their first 'Self Discharge Train' (SDT) appeared in 1988.
Produced in conjunction with aggregates firm Redland, this featured hopper wagons with a similar low level conveyor belt system. The main difference was that the belt now passed through several wagons, allowing unloading at the end of the rake. The initial order was for four 10-wagon sets, each comprising 8 inner wagons and two outers. There were two types of outer wagon, one with a diesel engine to power the conveyor and hopper doors, the other with a belt tensioning device and extension to allow sets to operate in multiple. All wagons were assigned the standard PGA TOPS code for 4-wheel hoppers. The inner wagons were numbered REDA16000-16031 to design code PG019A, the diesel engine-fitted outer wagons were REDA16100-16103 (PG020A) and the opposite outers were REDA16200-16203 (PG021A). The hopper on each wagon was V-shaped with no longitudinal taper (except on the outer wagons), and a pair of full-length clamshell doors at the bottom. Substantial vertical and diagonal bracing was fitted between the solebars and the hopper sides, giving a boxy appearance. The wagons were painted in Redland's pale green livery with company lettering in red on the hopper sides. Buffers were only fitted to the outer ends of each set, the inner connections being close coupled by means of a bar beneath the conveyor belt. Flexible hoses between each wagon transmitted air (or hydraulic) power.
To complete the system, an unloading vehicle was required. Without this, the entire load would be discharged onto the track at the end of the set. Two bogie container flats that had been built by Standard Wagon in 1985 were modified with conveyors belts for this purpose and recoded as PXAs to design code PX049A (REDA92545/92546). The first conveyor ran from one end of the wagon towards the centre, where it discharged into a small hopper. At the base of this was a longer second conveyor mounted on a turntable. When in transit, the raised end of this conveyor sat on a support framework at the other end of the wagon (underneath which was a further diesel engine and ancillary equipment). For unloading, the main conveyor could be rotated to either side to discharge the load into adjacent road or rail vehicles, or directly onto the ground.
With two unloading stations available, trains were typically formed of 20 hoppers and they first entered service in April 1988, running from Mountsorrel to various terminals. The design was particularly useful for short term flows where no unloading facilities were available.
Evidently successful, an order was placed for a second batch, delivery of which commenced in early 1989. Building on lessons learned from the first batch, the new order called for five 8-wagon sets, with the diesel engine repositioned to one of the inner wagons. The latter were numbered REDA16300-16304 (PG022A) while the unpowered inner wagons were REDA16032-16056 (PG019B) and the outer wagons REDA16204-16213 (PG021B). To work with these sets, an additional unloading station (REDA92635) was rebuilt from a bogie container flat. Later in 1989 two further SDTs were built for use by a Redland subsidiary in France. Although built to the European loading gauge, some of the hoppers were delivered to Dover by rail in an unfinished state. The remainder, plus the two unloading stations, were moved by road.
Outer wagon REDA16204 from the second batch was on display at the Railfreight '89 exhibition at Cricklewood in April 1989. Note that the bottom of the hopper rises towards the headstock at the outer end.
In January 1990, the TOPS codes allocated to private owner wagons were reshuffled to cater for the wider range of such types. The PH- series, which had been for bogie hoppers, became free and it was decided to use this to distinguish the self-discharge wagons from more standard hoppers. The Redland wagons therefore became PHAs, with the second letter of the design code changed to H (i.e. PG019A became PH019A). The unloading stations were similarly recoded as KJA (KJ049A).
REDA16056 was the last inner wagon in the second batch. By 2013 the TOPS code had been changed from PGA to PHA and the branding from Redland to Lafarge. The conveyor belt can be glimpsed behind the solebar. In front is outer wagon REDA16213.
A third order for domestic SDTs was placed in 1990 and delivered in the spring. As with the second batch, the new order called for five 8-wagon sets numbered REDA16057-16081 (inner wagons to PH019B), REDA16214-16223 (outer wagons to PH021D) and REDA16305-16309 (powered inner wagons to PH022B). Unloading station REDA92602 was a new build in 1992, similar to the earlier PXA/KJAs but to design code KJ050A.
For the second and third batches, the generator set was positioned on an inner wagon, such as REDA16307 seen at Hendon in 2013. Note the sloped 'roof' covering the engine.
The SDT concept appealed to the BR Civil Engineering department for use carrying ballast and spoil. This eventually led to the development of various bogie hopper designs of types YDA and YOA.
Apart from a change of branding to Lafarge Aggregates in about 2002, the SDTs continued in use on a variety of services from Mountsorrel. Some minor modifications by 2008 resulted in changes to design codes as shown below:
Unloading station REDA92602 was seen at Hendon in 2013. The shorter conveyor belt on the right takes material from the end wagon and deposits it in the conical silo. This discharges onto the longer conveyor, which could be swivelled to either side for unloading.
An incident whereby the conveyor boom of one of the loading station wagons was left 'out-of'gauge' and was struck by a passing train may have led to restrictions being put on the use of the self-discharge trains. By 2017 the wagons were out of use at Peterborough and they were all scrapped (by Booth's of Rotherham) that autumn.
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References: |
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Links: | N.B. Links will open in a new window. Photos of Self-Discharge Train (hoppers and unloaders) on Paul Bartlett's website Photos of Self-Discharge Train hoppers on Martyn Read's website Photos of Self-Discharge Train unloaders on Martyn Read's website Photos of Self-Discharge Train hoppers on Andy Jupe's website Photos of Self-Discharge Train unloaders on Andy Jupe's website |
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Notes: |
No notes have been left yet. ?There may be some notes posted but which have not yet been approved. |
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Data tags: ?Tags are mainly intended to show links to relevant profiles when looking at the detail page for TOPS codes, designs, batches etc. Here they work 'backwards' and will take you to the detail pages. |
Batch: REDA16000-REDA16031 Batch: REDA16032-REDA16056 Batch: REDA16057-REDA16081 Batch: REDA16100-REDA16103 Batch: REDA16200-REDA16203 Batch: REDA16204-REDA16213 Batch: REDA16214-REDA16223 Batch: REDA16300-REDA16304 Batch: REDA16305-REDA16309 Batch: REDA92602 Design/Diagram: KJ050A Design/Diagram: PG019A Design/Diagram: PG020A Design/Diagram: PG021A Design/Diagram: PG022A Design/Diagram: PX049A TOPS Class/Code: KJA Load Transfer Vehicle TOPS Class/Code: PGA 2-axle Hopper Wagon TOPS Class/Code: PHA (2) TOPS Class/Code: PXA Special Purpose Wagon |
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Added on: | 01/01/2008 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Edits: |
Record edited 1 time.
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