G-exam gees up GWR’s nocturnal ‘57/6s’

Great Western Railway HST & Locomotive Fleet Engineer Karl Atkinson talks exclusively to David Clough about the Class 57/6 Night Riviera locomotives’ ‘G’ exam programme.

Great Western Railway’s four Class 57/6s are nocturnal, going efficiently about their business six nights a week hauling the Night Riviera Sleeper service between Paddington and Penzance.

Routine servicing and maintenance is carried out at either the home depot at Penzance T&RS TD (generally referred to as Long Rock) or at Reading Traincare depot, where the trainsets stable during the day.

These four locomotives were converted from redundant Class 47s 20 years ago, when they were already nearly 40 years old.

Last year GWR, in conjunction with the locomotives’ owner Porterbrook, decided to put the fleet through a ‘G’ exam programme - the most extensive level of work carried out on a locomotive.

On January 21 2022, GWR owner FirstGroup had issued a tender notice inviting expressions of interest to design, build, test and commission between 15 and 30 bi-mode locomotives to operate with TransPennine Express (TPE) Mk 5A coaches, with an option for a further five locomotives for the Night Riviera.

The notice anticipated the upgrade of the trans-Pennine route (including electrification), at a time when FirstGroup operated the TPE franchise.

The routes of the Night Riviera are electrified as far as Newbury on the direct Berks & Hants line, and Bristol Parkway if the train is routed through Bristol to Taunton. The use of electric traction for part of the journey would therefore contribute to the green agenda.

The traction power had to be capable of hauling up to nine Mk 3 coaches weighing 344 tonnes tare mass, and with an electric train supply (ETS) rating of 340kW. They would also have to be able to work effectively over the steeply graded route through Devon and Cornwall. Communication between the locomotive and coaches was seen as preferable for dispatch and alarm indications.

However, the main impetus for this procurement disappeared when FirstGroup lost the TPE contract.

The Sleeper quintet was too small to form a bespoke order for locomotive manufacturers, so GWR looked around for an off-the-shelf design - but found nothing suitable.

Class 68s were well known to FirstGroup, but its engine noise issue made it unsuitable for use in Paddington station and at both Long Rock and Reading depots. Additionally, an inherently noisy engine was not the ideal traction on a Sleeper service.

GWR HST & Locomotive Fleet Engineer Karl Atkinson says his preference was for a six-axle machine to offer all-weather adhesion over the banks in Devon and Cornwall. Class 68s have just four axles, and there have been reports from other users about adhesion issues.

Another factor that had to be borne in mind was the views of the Department for Transport. The Night Riviera is a subsidised service, and the DfT must account for the cost of everything on the railway.

So, in 2023, with the 993,600 miles/ten-year milestone approaching for the Class 57/6s, GWR and Porterbrook decided to put the locomotives through a ‘G’ exam. This would be done by means of component exchange maintenance (CEM), whereby major items of equipment are removed and sent for specialist overhaul.

This concept is not new. When the Western Region planned the maintenance aspect of its diesel-hydraulic programme in the late 1950s, depots would remove equipment and send it to Swindon Works for overhaul, receiving an overhauled replacement in exchange, thereby cutting down the time out of traffic. British Rail introduced the same approach across the network in the late 1980s for the same reason.

In BR days, depots selected to carry out CEM were upgraded and received Level 5 status, which in many aspects of maintenance made them equal to a main works.

One such depot was Plymouth Laira, which continues to maintain GWR traction and rolling stock (except for the Hitachi Class 80x series of trainsets), and was selected to carry out the ‘G’ exams. The timing was useful because the depot’s workload was declining, owing to withdrawal of the High Speed Train ‘Castle’ sets.

Over the years, 57602-605 have been based at several depots. When GWR still operated Class 47s, it made sense for Swansea Landore to have them as well. The next move was to Laira, then Old Oak Common, and now Long Rock, the home of the GWR Sleeper fleet.

Meanwhile, 57601 was a prototype locomotive that was used by GWR, but was non-standard with the other four ‘57/6s’. It is now owned by West Coast Railway Company.

Clearly, any new programme involves a learning curve, and the ‘G’ exam programme is no exception. With the passage of time, Laira needed to refresh its Class 57/6 knowledge.

Work on the first locomotive (57604) has therefore taken longer than planned, it having entered Laira in October 2023. A four-month turnaround is envisaged for each of the other three machines - a tight timescale, but one that is considered achievable.

As for the work involved, the alternator and cooler groups, bogies and radiators have been sent to external specialists for overhaul, while the control cubicle has been sent for updating.

The biggest component is the General Motors Electromotive Division model 12- 645F3B two-stroke diesel engine. This delivers 2,750bhp at 954rpm.

Electromotive Diesels Ltd (EMD) at Longport specialises in the maintenance of General Motors engines, but was fully committed with work on Class 69 and ‘66’ power units. GWR therefore decided to carry out the overhaul at Laira.

Atkinson explains: “The engine is a whole new area. It’s been a long time since depots have done open heart surgery on an engine.

“I remember that with HST Valenta engines, pistons and liners replacement was an everyday thing. But even the bottom end work on a Valenta was a Crewe Works job.

“By contrast, modern diesel multiple unit engines are power packs, so it makes changing components fairly easy.

“Today, Laira is undertaking a full overhaul of the GM unit. We’ve had the crankshaft down and done all the engine bottom end. While EMD has been very supportive, it’s very much a learning process for the team who are doing the work. We’ve also had to manufacture cradles to support the engine while dismantled.”

Atkinson continues: “A second cradle was needed when we realised that we had to separate the crankcase from the oil pan to do the bottom end overhaul. The GM overhaul document suggests that you can do all the bottom end of the engine without removing the oil pan, but we soon realised that it would be a lot easier to split the oil pan off.”

Producing cradle stands for the dismantled parts of the engine entailed getting an engineering company to design and manufacture them, bring them to Laira, and check them. This added four weeks to the programme.

The GM ‘645’ engines are bespoke, in some ways.

Atkinson explains: “Material supply has been… I won’t say, easy. It became difficult to identify exactly what was needed, particularly when you get down to fasteners and gaskets and that sort of thing, which we have to work through. All the materials have to come from the USA, and you automatically get quite a long lead time because of the shipping.”

He gives a specific example that the engine rebuild is stopped, awaiting gaskets. But once the team has done the first engine and knows exactly the materials 100%, rather than 85%, then he thinks the next engine will be completed in much less time.

“The documentation that we work to is good, but we’ve already identified changes we can make to that, and we are effectively developing our own engine overhaul process,” he says.

“With all heavy maintenance, you learn a lot as you go along. We’ll see what happens in five years when they’ll be due for their next semi-major maintenance intervention.”

GWR’s ‘57/6s’ went through a spell of unreliability a while ago, due to a range of system faults, but matters seem to have improved. How does Atkinson see the situation? And does the ‘G’ exam include any reliability modifications?

“I’m comfortable with where we are, but it’s a locomotive-hauled train, so if it becomes a failure, it is end of service. The phrase ‘pyjamas on platforms’ was coined for such instances, but these are very rare, and this is why they generate great interest.”

Atkinson discusses a couple of areas that have affected reliability: “The last failure was with a battery block on 57603, which we hadn’t seen before. We’re aware that batteries are critical.

“The ‘645’ engine is not the easiest to start. If you can get a ‘57’ running, then you’re probably 90% of the way there. But the batteries are the critical part for starting an engine, so we do a lot around battery maintenance to make sure it doesn’t happen. And the battery block failure was something we couldn’t have predicted.”

Atkinson discusses a different issue that arises due to the age of the locomotive, which can cause a failure.

“Windscreen wipers offer a good example. You lose a wiper, you have to turn your locomotive, or you’re a failure. Obsolescence is our biggest challenge, and that’s where windscreen wipers is an issue.”

While Atkinson refers to the small number of wiper motors on the GWR fleet, other operators also have Class 57s. But perhaps even the combined total offers insufficient interest to the manufacturer.

He explains that GWR has a small team that works in the background dealing with out-of-date equipment: “We are actually looking at a replacement wiper motor, which will save us a lot of money and overcome the obsolescence issue.”

He also draws attention to another potential cause of locomotive failure that is being addressed.

Low power reports were being caused by dirt in the fuel tanks. A programme of tank cleaning was implemented… and the problem went away.

Atkinson has been looking at a revised fuel pick-up solution for the tank. The FuelActive system is a modification being offered by Unipart Rail, and it is being tested on 57604. The system uses a floating pick-up unit which draws fuel from just beneath the surface of the fuel in the tank, to avoid contamination and to ensure that the cleanest fuel is passed into the engine.

The FuelActive solution has been used on a number of diesel multiple unit fleets. Unipart Rail claims a fuel saving of up to 5%, and Atkinson calculates that even a 2% improvement will pay for the equipment.

It appears the ‘G’ exam work is creeping into re-engineering, albeit in order to offer reliability improvements. Does Atkinson agree?

“Not at all. It is definitely core heavy maintenance. My engineering director would probably say that it’s a ‘G’ exam, but if there’s an opportunity to implement any of the small modifications that we have waiting to go in, then we will do it. The ‘G’ exam is purely heavy maintenance, and there’s no significant changes at all apart from an opportunity to fit some modifications.”

He continues: “To be honest, the core workload for a ‘G’ exam on the ‘57s’ is quite significant, especially when you come to corrosion. It is only when you start dismantling the locomotive that you find its full extent, and there has been a lot of corrosion on 57604.

“You have the usual cantrail side panels, as well as some of the body side behind the fire bottles in No 2 end, because that was an area that has always suffered for various reasons. Then there are the underframe conduits, once you take down the spark guards, dragboxes, headstocks, subframe and the solebar.”

Corrosion in the cab floor was a probable source of draughts. This has been addressed and the floor covering has been replaced. There is praise for the team at Laira - particularly the fabricators and welders, who have done an excellent job.

With all the major components removed, has there been any internal painting?

“Laira has done an excellent job of an internal repaint. We haven’t done the cabs yet, and I’m reluctant to paint these because the paintwork is very good. By the letter of the law, it would be a touch-up. But in my experience, touch-ups tend to make things look worse.”

However, Laira has done quite a lot of work in the cabs, notably on the droplight windows and the doors.

Atkinson explains that drivers always have a shopping list, and Laira is doing what is possible to help them within the confines of a Class 57 cab. The seats were tired and have been replaced across the fleet during the past year, and drivers are happy with that.

Cab air-conditioning is also on drivers’ wish list, but the space available to fit equipment is very limited. Class 57/3s have a cab fan fitted, and Laira is rolling this modification out across the ‘57/6s’ as well.

While 57604 has been dealt with, it is uncertain whether there will be time during the ‘G’ exams on the other three locomotives, so that work may have to wait for a later opportunity.

Wiring insulation was found to be satisfactory. So, once 57604 has been reassembled, the engine will be started, and the locomotive will be hooked up to Laira’s load bank to ensure that the engine is running at the book maximum of 954rpm when in notch 8 full power.

Of course, the GWR ‘57s’ are not the only examples still owned by Porterbrook.

Atkinson reports that he is working closely with the leasing company and the Class 57 platform. The Class 57 Users Group will meet at Laira in May, with the purpose of sharing information and improving documentation and the products.

Atkinson makes clear that GWR works closely with GB Railfreight, Direct Rail Services and Locomotive Services Ltd, all of which operate Class 57s.

In hindsight, in view of the extent of the work that has gone into the ‘G’ exam so far, would a different solution have been better?

Atkinson initially says “perhaps”, but then adds “better the devil you know”. He goes on to say that the ‘57/6 is quite a reliable machine, and that GWR has a small fleet which is managed closely. The shopping order for the other three locomotives is expected to be 57603, 57605, and finally 57602.

Turning briefly to day-to-day operations, the locomotives are at the London end stable at Reading during the day, and are serviced there. Routine maintenance is performed on a balanced ‘B’ exam cycle, both at Reading and at Long Rock.

In the evening, the train leaves the depot with a locomotive at each end, because there is no shunt release facility at Paddington. On arrival at Reading on the westbound journey, the rear locomotive which pulled the train to Paddington is detached and returns to Reading depot.

This arrangement is reversed in the morning, when the eastbound service reaches Reading, so that the locomotive attached at the rear there can haul the empty stock out of Paddington.

How does GWR calculate the fleet mileage?

“We work on 900 miles per day across three locomotives, which is based on 337½ miles for the Sleeper service via the longest route and 37½ miles for the empty stock moves between Reading and Paddington , and 150 miles for the pilot locomotive .

“Doing this six nights each week gives us 5,400 miles per week, which equates to 21,600 miles per period, so annual fleet mileage becomes 280,800. This makes no allowance for reduced operation over the Christmas period.”

Not directly part of the ‘G’ exam work, GWR has 57312 on sub-lease from GB Railfreight to act as a Thames Valley Thunderbird to recover failed trains or when the overhead power wires are brought down.

The only significant difference to a ‘57/6’ is the fitting of a Dellner coupler. GWR has made several modifications and expects to keep the locomotive until the end of its contract with the DfT.

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