Mike Humble:

Over the past few decades, the UK based truck and bus industry has swallowed more than its fair share of bitter pills. One by one many of the once great and mighty truck and bus names have faded away into the ranks of memory, nostalgia or simply… forgotten. What many people fail to consider is the knock on effect to the supply chain as the vehicle manufacturers disappear into oblivion. Some component suppliers were almost as well regarded as the manufacturer whose major parts were quite often the heart of the final product.

The key component of any motor vehicle is the power unit and so far as commercials and PSV chassis matter, the UK was once home to some engine makers of global repute. Great names such as Gardner and Rolls Royce powered many vehicles from the stables of AEC, ERF, Foden and Scammell – all of the aforementioned have either been lost through acquisition or through the decline of our manufacturing industry over recent decades. Those engine builders who still have a UK presence such as Perkins and CAT have since retrenched from automotive applications to concentrate solely on the less glamorous construction or power generation sector.

The good news is we still have a major truck builder (DAF) and a collection of bus manufacturers in Britain along with their supplier of engines. American owned Cummins have enjoyed a solid UK presence since 1956 when it opened its first engine plant in Shotts Lanarkshire to service a nearby construction equipment plant with power units and other engines for various rail based projects. To this day, Cummins UK still remains heavily involved with rail and locomotive power through its Daventry facility. So if you ever wondered where that thrum and power comes from when travelling in a Virgin Voyager train… you have Cummins to thank for that!

The Higgs and Hill constructed Darlington facility came on-line in 1965 through a joint venture with Chrysler and this year celebrates its 50th anniversary of engine production in a town that is synonymous with engineering excellence. Cummins first foray into the bus market came with its V6 engine being fitted to a Daimler chassis. In fact Darlington Corporation Transport – barely a mile from the factory, bought a batch of twelve Roadliner buses in 1967. Its earliest automotive products were no match for the likes of Gardner or Rolls Royce for reliability or reputation, but it listened to operators and engineers views and concerns… very carefully. Cummins went on to dissolve the Chrysler tie-in and tackled its early reliability issues head on with development engineers on both sides of the Atlantic turning the fortunes round to where they are today – the world’s largest and most respected independently owned engine manufacturer.

But it hasn’t all been sweetness and light over the years at Darlington. The slump in vehicle sales in the early ’80s caused by a general recession forced Cummins to scale back production and cut costs. By the middle of the decade, the component plant operating next door to the assembly lines that provided parts, castings and other raw components was sadly closed down… as was the production site at Shotts in Scotland. But worse was yet to come – now the threat of total shut-down at Darlington was imminent and making national news. During this very difficult period the hundreds of workers, the plant managers, Darlington townsfolk and local politicians rallied round to plead their case to the Cummins hierarchy. Without a new product in the pipeline or a huge upturn in business… Darlington seemed doomed.

The plant at this time produced components and V engines for export but when this ceased there was little to keep Darlington viable hence the total shut down plan – but the plant pulled through. In 1986, with an upgrade which cost of over £13.5 million, Cummins re-fitted the Darlington plant for production of the all new multi-purpose “B Series” engine in both 3.9 and 5.9-litre capacities. The larger 5.9 litre unit became the sole power unit for the revised Leyland Roadrunner – the engines first major recipient, with rival manufacturers such as Dennis, ERF and Foden eventually taking the B Series unit for their bus and truck ranges after the engine very quickly gained a superb reputation for economy,

Leyland were starting a process of running down its own engine production, it realised that to make a global success with its vehicles it needed to out source its power units and this new engine looked ideal. The well received Roadrunner of 1984 may have looked new inside and out, but the engine was an ageing design called the 6.98 series. Despite a recent improvement programme, the 6.98 was at the end of its design scope. Leyland had decided they were to design and build no more new designs for future requirements, besides, their reputation for engines was only at best – tolerable. Cummins had been supplying Leyland with heavy truck engines for some years, but a new venture was being put together to bring a whole new dimension to customer / supplier collaboration.

An engineering alliance team between Columbus USA, Darlington and Leyland was formed to develop the Cummins B unit into a perfectly honed installation for its first UK recipient – the Roadrunner. Some strict design criteria ensured that items such as the alternator compressor, fuel pump, manifolding and ancillary components were fitted in ideal places to match the chassis of the truck and contribute towards reduced downtime. This was more than just a bought in engine, it was a fully developed package tailor made for the Roadrunner that had more testing and development work bestowed upon it than any other truck engine at that time. Cummins own testing alone amounted to some 170.000 hours and nearly 12.5 million miles. The Cummins – Leyland alliance was hugely successful and continues this day with DAF.

Engines that were produced to Leyland Trucks specification were submitted to three phases of further testing that included 1500 hours running at full power with periods of shut down, 2500 hours at rated engine torque and a gruelling 3500 hours of 5% overfuel and 10% over-speed over a cycle of max speed, idling, max speed and shutdown. Development drivers also tested a prototype chassis by downshifting the gearbox almost 10.000 times to simulate a 50% over-speed of almost 4200rpm, the Cummins B series even shrugged this manoeuvre off. Key to this new engines inherent strength was massive bearing surfaces, a rigid cylinder block, effective cylinder head clamping and state of the art production facilities with all parties being focussed on a right first time approach to engine building. At the point of launch, this all new design was by far the most tested and proven diesel engine in the world.

Needless to say, the B series became an instant hit with drivers, operators, fitters and the motoring press who applauded its modernity, its frugality, its reliability and low cost of ownership. And yet the B series was an seemingly unexotic design brief that featured a simple bored block construction rather than using cylinder liners and it was not even originally designed to be reconditioned when it a unit finally became life expired. The engine not only breathed new life into existing truck designs, it soon became a popular choice of which to re-power older vehicles. Bedford buses and coaches were still popular with low cost operators and a fully backed conversion called Bedford Re-Power found the Cummins B series even more customers.

Six cylinders… 5.9 litres… On two wheels!

“I couldn’t believe just how car-like the little Roadrunner felt with its pin sharp, rock steady handling and instant performance, it was in a different league to my last lorry experience and the job went without a hitch… a lovely truck and engine” – Russ Swift describing his thoughts on the Cummins powered Roadrunner

It seems no matter who you speak to about the “B” series, irrespective of their experience or exposure, the engine comes in for high praise. Even the odd celebrity has had some kind of tangible experience with the engine. Many will have heard of Russell Swift – the well-known stunt driver who became a household name thanks to the famous Austin Montego TV advert. Russ had done a similar two wheel driving publicity stunt for the newly formed AWD Trucks business but not without incredible stress. He told me; “The handling and performance of the AWD was so worrying and unpredictable that the whole experience actually gave me an ulcer with stress trying to get the trick right… which I did but I vowed never to do it again in a truck”.

So when Ever-Ready contacted him to do some publicity stunt work in a Leyland Roadrunner, he rather swiftly (no pun intended) declined the offer. However, they were persistent and Russ eventually agreed to test drive the truck before committing fully at the Croft racing circuit. Russell told me recently with total recall; “I couldn’t believe just how car-like the little Roadrunner felt with its pin sharp, rock steady handling and instant performance, it was in a different league to my last lorry experience and the job went without a hitch… a lovely truck and engine” – the latter being a good testament for the Darlington built 5.9 litre Cummins B. Just like the engine in the truck in question and indeed myself, Russ is a Darlingtonian born and bred. When I asked him if he knew the engines locality he just grinned, shrugged his shoulders and quipped “aye… well there you go you see” – Nice one Russell!

I recently visited the Darlington plant to witness the current Euro 6 range of engines being produced – my first time there since 1987 as a schoolboy. For someone like me who fully understands modern technology in an engine, I still walked away breathless with admiration at the rapid advance of quality and technology for the diesel engine. It was not that long ago that a diesel engine didn’t even require an electric current to run, yet they now harness more technology and development than your average petrol car and it’s us Brits who lead the field in diesel engine emission technology – I’m quite proud of that. But Darlington also plays a massive role in green engines, its home to Cummins Emissions Solutions who develop, test and manufacture a range of emission filtration / after-treatment and exhaust catalyst systems in a very clean laboratory type environment.

Over 1.5 million engines have been produced so far and well over 100.000 emission systems on top of that, which is an impressive figure. Its latest engines are just as popular world-wide. Yet Darlington still produces the B Series along with the 8.3 litre C Series units in diesel and gas format for marine and power generation purposes only. The present range of engines for automotive use are the four and six cylinder 4.5/6.7 litre ISB and 8.9 litre ISL engines with the first two letters standing for Interact System which is Cummins’ patented electronic fuelling and telematics control programme. The bulk of Darlington’s output is destined for automotive-based applications, others are destined for power generation, plant and marine use.

Despite what pundits may have you believe, we are producing more cars, vans, trucks and engines in the UK than we have done in long while. Cummins quite rightly recognise that Darlington is a centre of excellence within engine manufacturing thanks not only to the quality of the engines but the key attribute of the finished product – the staff who work there. The Yarm Road premises that are situated on the extreme east side of the town that’s steeped in engineering history currently employs over 600 people involved with the manufacturing of engines to over 2000 differing customer specifications.

There is a nice relaxed atmosphere as you meander amongst the men and machines inside the factory and the feeling of camaraderie in the huge works canteen during the lunch break was more than obvious. But what did impress me the most was the attention to detail and cleanliness everywhere you look, I had a good look at a finished unit awaiting its next move to the paint booth. Not a single burr or ragged edged casting could be spotted and the factory is very highly mechanised too. But it takes a human touch to have that all important eye for quality… and it’s certainly noticeable too.

Operator Insights:

But how do the Darlington built engines perform out in the field and more importantly – a few years down the road? I took time out to visit a good friend and customer of mine Austin Blackburn, owner of Go-Coach Hire in Sevenoaks to ask his frank and honest opinion. As friendly as they come but brutally honest as they go, Austin is a big fan of Cummins engines with the bulk of his service bus fleet being powered by Cummins units from the four cylinder iSB up to the legendary L10 unit. Even his brace of heritage AEC Routemasters have been re-powered with a turbocharged B and a de-rated 8.3 litre C series.

“They’ve been invaluable and I can probably say that we couldn’t and possibly dare I say wouldn’t have built the business to the effect that we have today without hard grafting buses with dependable power units” – Go-Coach Hire Owner and Mechanic Austin Blackburn on the importance of a good engine

Owner Austin was keen to point out how dependable and reliable a Cummins engine is; “I’ve been working on these engines since 1988 and have found the B series, especially in Euro 2 format unbeatable. The back up is best in the business and they can be bulletproof. In good order they run smoothly and just go seemingly forever… they just get on with the job”. Have they been that much of an asset to his business I asked him; “most certainly” he expands with; “They’ve been invaluable and I can probably say that we couldn’t and possibly dare I say wouldn’t have built the business to the effect that we have today without hard grafting buses with dependable power units”.

Not only does he run a bus and coach operation, Austin is also a time served fitter who did his apprenticeship with London Transport. His other company, The Bus Doctor, specialises in 3rd party maintenance and repairs for PSV and light commercials. They have extensive experience with current Cummins engines too. Austin was keen to point out that even though the current Euro 6 criteria has given many engine builders and operators something of a headache. He stated; “I doubt any other manufacturer has invested so much time and money into engine emissions” – he could be right.

Learning and progressing from their earliest foray into PSV chassis, Cummins have certainly helped the UK bus industry succeed to the point where they are today. The Transport De-regulation Act which came into effect in 1986 caused a great deal of heartache and uncertainty in the industry for operators and chassis builders. But it opened up the marketplace towards smaller buses rather than lumbering double deckers and Dennis were keen to exploit the new trend of midi-buses with the game changing Dart. Subsequent models such as the Lance to the present Enviro 2/3/400 range all rely on Darlington built Cummins power units, Optare and Wrightbus also followed suit and continue to specify Cummins

Every UK based bus builder from ADL through to Wrightbus use the current Cummins ISB in four or six cylinder option. The company has well and truly beaten the record for the UKs most used engine for bus applications which was formerly held by Gardner. A sobering thought is the demonstration of progress and modern technology, especially when you consider developed power at the flywheel. The current 4.5 litre four cylinder ISB unit develops more power (up to 210PS) than the 182Ps that a Gardner 6LXB could muster from its massive 10.45 litres in the early ’90s.

Bringing it all back home:

As with many other global companies, Cummins have plants overseas to suffice local markets or to make a product cost efficient. The current Euro 6 four cylinder ISB engine is produced in China but all that is to change in the not too distant future. In the quest of better lead times to mainly cater for the UK bus manufacturing industry, Cummins have decided to bring production of engine to Darlington which takes effect as of later this year. The news is a great morale booster and is reckoned to be boosting engine production by an extra 1000 units annually.

Worthy of celebration indeed but Cummins have that covered too. To commemorate 50 years of the factory, the company is holding an event on July the 11th at the Darlington site. They are keen to source the oldest Cummins powered vehicles still on the road to join their display of vehicles. If you own or know anyone who runs a heritage Cummins powered bus or truck who may like to join in the event, contact Steve Nendick on 01325 556717 or send an email to steven.nendick@cummins.com for further information.

To conclude, it’s fair to say that Cummins in the UK has an illustrious past, a respected present and a bright future in engine manufacturing – and long may it continue.

Happy 50th Cummins Darlington!

Thanks are due to Mike Brown, Tim Hamilton and the good folk at the Darlington plant for their great hospitality on the day. Also to Russell Swift and Austin Blackburn for their thoughts and experiences they have shared.