British Rail Class 143

The British Rail Class 143 is a diesel multiple unit, part of the Pacer family of trains introduced between 1985 and 1986. They originally worked in the North-East of England but were later transferred to Wales and South-West England.

Under the Disability Discrimination Act 1995, all public transport will need to be accessible by 2019. Pacers do not meet this requirement and so will all be withdrawn by the end of 2019.

Technical
At around the same time as the British Rail Class 142 was in development, a Pacer railbus was being developed by Kilmarnock-based Hunslet-Barclay. The train used a Walter Alexander bus body and entered service in 1985. Again with 2 × 205 bhp motors giving a total output of 410 bhp and a top speed of 75 mph, the class originally had a capacity of 122 passengers per 2-coach unit.

As with all Pacer units, the 2-axle non-articulated wheel arrangement has given rise to problems with wheel noise on low-radius curves and poor ride quality in general. The interiors were completely changed in 2000, with bespoke Chapman high-back seating installed throughout, along with improved fittings, replacing 2+3 bus-style low-back seating; this reduced seating capacity to 106 seats per set.

North East
The class was based at Heaton depot (Newcastle) from new, for use in the North East of England on services based around Newcastle, Darlington and Middlesbrough. Of the original twenty-five units built, 143001-019 were supplied in Provincial railbus-style two-tone blue livery, and 143020-025 were supplied in Tyne & Wear PTE yellow+white livery.

As with the similar Class 142 units, problems soon emerged with the SCG mechanical transmission, resulting in poor availability, and frequent loco-hauled substitutions by Classes 47 / 31 on local services to Middlesbrough / Carlisle, especially in 1987, continuing to a lesser extent in 1988 and 1989, as the units were progressively fitted with the more robust Voith hydraulic transmissions. Improved availability of the units - coupled with the influx of several former West Country Class 142 units - enabled the Class 101s to be eliminated from Heaton depot in 1989... meanwhile the loco-hauled substitutions also dwindled to typically one set diagram per day, finally ending altogether in Summer 1990, by which time the Pacers had generally settled down to give more acceptable reliability.

During the problems, a total of four original formations were split, and reformed to make operational DMS-DMS(L) sets, in a bid to alleviate the acute DMU shortage in the region. First to be split were 143002 and 143010, and cars 55643+55676 actually carried unit no. 143026 for a time in 1988. However, the pair was later renumbered 143010. The other cars 55651+55668 appeared later in 1988, with 55651 having a large white number 2 - meant for coach sides - crudely placed across the black 10 of its original unit number, only rectified upon later renumbering to 143602...

In 1989, Heaton depot implemented a unit renumbering scheme, whereby those with original SCG mechanical transmission would be renumbered 1433XX, and those that had undergone conversion to Voith hydraulic transmission would be renumbered 1436XX. By this time, many units had already received Voith transmission, so were renumbered directly from 1430XX to 1436XX. Only the T&WPTE-sponsored units - which received Voith transmission later on - actually carried the 1433XX series, renumbered to 1436XX when they were eventually converted.

143003 had spent a lengthy spell out of action with fire damage, then in Summer 1989, car 55644 from it was paired with 55683 (ex-143617), and both given the unit number 143617. The other cars 55658+55669 re-appeared later that Summer, both carrying unit number 143603. These reformations were never reversed to original formations, thus 143602, 143603, 143610 and 143617 remained mis-formed ever since.

143025 did carry the name of 'River Tyne' for sometime when it was based in the North East

Wales
From 1991/92, the units started to be transferred to Cardiff Canton depot for operations in South Wales, and moved over to Wales & West control during privatisation. It then passed on to Wessex Trains, which became part of the Great Western franchise. Arriva Trains Wales uses its Class 142 trains on commuter lines around Cardiff to places such as Rhymney, Aberdare and Barry Island. Additionally, Arriva has deployed 143s on longer journeys, such as those from Cardiff Central to Carmarthen, Swansea, Pembroke Dock and Fishguard Harbour.

It operates 15 sets. A 16th set (143615) sustained severe fire damage during 2005 and has now been scrapped at Cardiff Canton. Arriva's fleet was repainted in turquoise and cream Arriva Trains Wales livery. 143609 has been named 'Sir Tom Jones' in honour of the Welsh singer.

Arriva Trains Wales began a minor interior refresh of its Class 143s in Autumn 2009. The seats are being retrimmed into the Arriva moquette. Additionally on the exterior of the Class 143 Pacer trains, LED head and rear marker lights and LED door obstruction marker lights are being installed.

South-West England
Wessex Trains used their fleet primarily on commuter services around Bristol, although towards the end of the franchises they were increasingly on longer distance Cardiff Central to Taunton services. They were occasionally used on rural branch lines but this was generally avoided where possible due to problems with wheel wear and the noise on sharp corners.

First Great Western inherited the seven Wessex Trains units when the franchises were merged in April 2006. An eighth set used by Wessex Trains (143613) caught fire near Nailsea and Backwell in October 2004 and was scrapped.

In Autumn 2008, the Class 143s began a further refurbishment program at Eastleigh works; the interior improvements include:
 * New 'easy to clean' flooring
 * A retrim of the existing Chapman seats with First Great Western moquette
 * Refurbished toilet area with new flooring, wall coverings, toilet and sink basin
 * Brighter interior saloon fluorescent lighting diffusers

Since December 2008 the Class 143s are based at Exeter TMD alongside seven similar Class 142s. They are now allocated to the following services:
 * Avocet Line Exmouth - Exeter St. Davids
 * Riviera Line Exeter St. Davids - Newton Abbot - Paignton
 * Tarka Line Barnstaple - Exeter St. Davids

Incidents
On 17 October 2004, Wessex Trains unit 143613, forming the 20:06 2W63 service from Bristol Temple Meads to Weston-super-Mare with 143621, caught fire between the site of the former Flax Bourton railway station and Nailsea and Backwell. Fire services took two hours to get the blaze under control. Of the 23 passengers and crew three were treated on-site for the effects of smoke inhalation. One carriage was completely burnt out, and the other was badly damaged, causing the train to be written off. The line through Nailsea was closed until 03:30 the following morning, when the train was hauled to St Philips Marsh Traction and Rolling Stock Maintenance Depot for examination. The unit was later taken to Crewe Works where it was stored, then later to Cardiff Canton TMD where it was scrapped. The Rail Safety and Standards Board issued a report into the incident, concluding that the fire was caused by electrical arcing between the live starter motor cable (which had damaged insulation) and the unit's underframe, causing accumulated oily residues to ignite.