The Anonymous Widower

The Future Of The Class 68 Locomotives

This post has been brought on by the comments to two posts I have written today.

Both Direct Rail Services and TransPennine Express are major users of Class 68 locomotives, with each having a fleet of fourteen locomotives.

In addition, Chiltern Railways has a smaller fleet of six locomotives.

  • Direct Rail Services use their locomotives for various passenger and freight duties, including the important one of moving nuclear material around the country.
  • TransPennine Express use their locomotives on their passenger services across the North of England.
  • Chiltern Railways use their locomotives on their passenger services between London and Birmingham and sometimes Oxford.

The design was a bespoke one by Stadler for Direct Rail Services and the first one entered service in 2014.

The picture shows one of TransPennine’s Class 68 locomotives at Scarborough. As the picture shows, they are a smart and purposeful-looking locomotive, that wouldn’t look out of place in the right livery on the front of the Royal Train.

It has some good features.

  • It is a 100 mph locomotive.
  • It seems to be well-liked by operators.
  • It can haul both passenger and freight trains.
  • It can act as a Thunderbird or rescue locomotive.

But they have three problems; emissions, noise and diesel.

This is from Wikipedia.

The locomotive’s propulsion system is compliant with Stage III A of the European emission standards, but not the more stringent Stage III B requirements.

But noise is a another problem and this has caused council action in Scarborough.

More important than emissions or noise, is the fact, that the locomotive is diesel-powered, so the fleet will probably have to be retired from the railway, at a time, when there is still useful life left in the locomotives.

The Class 68 locomotive is a member of the Stadler Eurolight  family, of which there are three versions.

All follow similar design principles, differing mainly in dimensions, with Spain, Taiwan and the UK ordering upwards of twenty-thirty locomotives.

The UKLight branch of the family has two other members.

The Class 88 locomotive is an electro-diesel version of the Class 68 locomotive and the development of the design is described in this extract from the Class 88 locomotive’s Wikipedia entry.

Amid the fulfillment of DRS’ order for the Class 68, Stadler’s team proposed the development of a dual-mode locomotive that could be alternatively powered by an onboard diesel engine or via electricity supplied from overhead lines (OHLE). Having been impressed by the concept, DRS opted to place an order for ten Class 88s during September 2013. Having been developed alongside the Class 68, considerable similarities are shared between the two locomotives, amounting to roughly 70 percent of all components being shared.

According to Wikipedia, the type had a smooth entry into service.

The Class 93 locomotive will be the next development of the UKLight branch of the family, when it is delivered in 2023.

It will be a tri-mode locomotive, that will be capable of being powered by 25 KVAC overhead electrification, an onboard diesel engine and batteries.

It will be a 110 mph locomotive.

It can haul both passenger and freight trains.

Rail Operations Group have ordered 30 locomotives.

This is the first paragraph of the section in Wikipedia called Specification.

The Class 93 locomotive has been developed to satisfy a requirement for a fast freight locomotive that uses electric power while under the wires, but is also capable of self-powered operations. Accordingly, it is capable of running on diesel engines, from overhead wires, or from its onboard batteries. These batteries, which occupy the space used for the braking resistors in the Class 88, are charged via the onboard transformer or regenerative braking; when the batteries are fully charged, the locomotive only has its friction brakes available. The diesel engine is a six-cylinder Caterpillar C32 turbocharged power unit, rated at 900 kW, conforming with the EU97/68 stage V emission standard. The batteries units are made of Lithium Titanate Oxide and use a liquid cooling solution, enabling rapid charge and discharge.

It is a truly agnostic locomotive, that can take its power from anywhere.

The last paragraph of the specification compares the locomotive to the Class 66 locomotive.

In comparison with the Class 66, the Class 93 can outperform it in various metrics. In addition to a higher top speed, the locomotive possesses greater acceleration and far lower operating costs, consuming only a third of the fuel of a Class 66 along with lower track access charges due to its lower weight. ROG has postulated that it presents a superior business case, particularly for intermodal rail freight operations, while also being better suited for mixed-traffic operations as well. Each locomotive has a reported rough cost of £4 million.

It is no ordinary locomotive and it will change rail freight operations in the UK.

I have a feeling that the Class 93 locomotive could be a lower-carbon replacement for the Class 68 locomotive.

But I also believe that what Stadler have learned in the development of the Class 93 locomotive can be applied to the Class 68 locomotive to convert them into zero-carbon locomotives.

It may be just a matter of throwing out the diesel engine and the related gubbins and replacing them with a large battery. This process seems to have worked with Wabtec’s conversion of diesel locomotives to FLXdrive battery-electric locomotives.


January 22, 2022 - Posted by | Transport/Travel | , , , , , , , , , , , , ,


  1. I can’t agree with you that the fleet will probably have to be retired from the railway, because it’s a diesel, diesel will phased out by 2040. While they won’t have the longevity of most locos it will probably make the 20 years plus mark. It’s going to be that pesky noise issue that are going to relegate it to freight duties well away from most the passenger operations.
    It would be great to think they might consider converting the Class 68 to the Class 93 particularly if the conversion of the Class 68 into a tri-mode could be done back in Valencia, and especially if it could be arranged to dovetail in with the procurement of the Class 93. Think of all those extra C32 engines, the extra battery packs and the traction transformer, not forgetting the pantographs.
    The class 93 may have an efficient diesel unit onboard, but the traction battery pack is Lithium Titanate, the sort of battery that provides short duration operating without the backup of the diesel engine, so the three modes of operation will be, full electric freight, hybrid light freight/passenger operations and diversionary running, or ‘last mile’ battery necessities. I don’t see any point in regearing them though.
    Thyristor control may have been superseded by the IGBT, but that was 25 years ago. At one time, wheel slip control that activated within an eighth of a wheel revolution, said the ROG, would be industry leading performance but that was back in the late 1980s early 1990s when the limit of the coefficient of adhesion between wheel and rail was around 0.33. By 1990 Krauss-Maffei had been involved in a system that could respond within 15 degrees of wheel rotation, a third of the time cited in the ROG interview and my memory of American heavy haul locomotives was that they were well in advance of general European wheel adhesion performance by the late 1990s and talking about the achievable limit of adhesion as being in the order of 0.38 – 0.4. I’d love to know what level they are aspiring to now.
    Anyway the wheel adhesion control system built into the class 93 is almost instantaneous and that can only be advantageous, but that’s largely down to advanced mathematical modelling techniques of the traction system itself and the intervening research on wheel-rail behaviour under dynamic and environmental conditions. Think how much better it would be if the Class 93 had more than the one traction inverter shared between four motored axles so that you could have independent control of each axle.

    Comment by fammorris | January 23, 2022 | Reply

  2. I disagree with you about diesel. In the Sunday Times today, there is an article, which is entitled “Aviva to eject company directors if climate goals are not met”. I can see transport companies racing to zero carbon. First Group is already working with Hitachi to reduce the carbon footprint of their trains and elimination of diesel locomotives would please institutional investors and help the share price.

    Lumo, who are a First Group company certainly play the carbon card in their marketing.

    Comment by AnonW | January 23, 2022 | Reply

    • A year ago Zelda Bentham, Aviva’s Group Head of Environment and Climate Change, said: “When we look at companies involved in thermal coal, for example, it might be that only 15% of their revenue comes from thermal coal and the rest from renewables, so what is a thermal coal company to one person may be viewed as a renewable energy company with some legacy fossil fuels to another.
      “Even with the best companies in the world, there’s always something that won’t sit well with one or more groups or individuals. There’s a balance that we need to get right and that’s where environmental social and governance considerations (ESG) come into effect.
      “The focus of ESG is not how ethical you believe a company to be because there’s such a wide range – from adult entertainment to gambling through to fossil fuels through to controversial weapons. It’s up to your personal values on whether it’s ethical or not .”
      Aviva are right to encourage activities that do no harm to the planet but I’ll take the report in The Times with a pinch of salt.

      Comment by fammorris | January 23, 2022 | Reply

  3. Sadly, in London and elsewhere a lot of freight moves along passenger lines, so relegation of noisy locos to freight only duties isn’t really a solution.

    Case in point are the freight trains that run on North London line and onwards through Stratford towards eastern destinations. These routes do have partial electrification to varying standards which should benefit from hybrid traction.

    GBR could choose to subsidise a rapid changeover (especially for passenger use), with excess existing units resold internationally or maybe converted.

    Comment by MilesT | January 23, 2022 | Reply

    • I use the North London Line and Goblin a lot. It annoys me to see diesel freights running under the wires, when the whole route is electrified.

      Many more duties could be zero-carbon with Class 93 locomotives or a battery-electric conversion of a Class 68. Both locomotives would also speed up freight trains, which could create extra paths.

      I must admit, that I have been surprised at the speed of Wabtec’s progress with battery-electric trains and their orders, but that says to me that a lot of corporate boards are serious about decarbonisation. Probably, because it helps the share price.

      Comment by AnonW | January 23, 2022 | Reply

    • I realise I didn’t express myself as comprehensively enough as I’d like, but in thinking about the Class 68 I’m aware that the noise problem is essentially one where the freight train is at low speed or stopped. On the more general point of all diesel electrics, freight trains running on North London line and onwards through Stratford towards eastern destinations have to be discouraged Any solution that helps has to be encouraged. I used to live within 50 metres of the London – Portsmouth line and although we only had two freight trains a day but we were more than aware of those Class 58 locos thumping away with their Ruston Paxman 12RK3ACT slow speed engines that redline at about the idling speed of a modern Caterpillar C175. There’s a lot more than Class 68s that need attending to.
      It would be nice to think that GBR would choose to subsidise a rapid changeover. As it stands GBR will have a statutory duty to promote rail to secure economic, environmental, and social benefits for the nation The government issuing guidance on its priorities for rail freight in each funding settlement intrigues me more. Let’s hope sufficient independent to finance rolling stock replacement, personally I think as described at present GBR’s policies will be at the discretion of the Treasury and the DfT – scary and something politicians will want to distance themselves from.
      Reselling excess UK locos is not impossible but not easy as can be witnessed with limited sales to Europe in the last 30 years generally in aid of construction projects, or the odd infrastructure support requirement. That still leaves a lot of surplus stock.
      Judging by Nigeria’s recent decision to purchase two surplus two 330km/h Talgo trainsets from the USA to run on a 37 km metro system, maybe we should be flogging unwanted stock to Accra

      Comment by fammorris | January 23, 2022 | Reply

  4. Accra? Not sure about railways in Ghana. Surely, you mean Abuja! Although, it looks like the trains will be running a commuter service in Lagos

    Comment by AnonW | January 23, 2022 | Reply

    • Yes got my A’s mixed up, but it’s actually Agbado in Lagos State.

      Comment by fammorris | January 23, 2022 | Reply

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