The Anonymous Widower

The Ultimate 125 mph Bi-Mode Train

This post puts together my thoughts on 125 mph bi-mode trains from other posts in the last couple of months.

Yesterday, I had my first ride in a Class 800 train. I went from Paddington to Swindon in two-five car trains, working as a ten-car formation.

  • The route is fully-electrified between Paddington and Didcot Parkway station
  • The train was full.
  • The train was doing 125 mph for substantial parts of the electrified route.
  • On the sections without electrification, a lot of the running was over 100 mph.

I didn’t notice any noise or vibration from the diesel generators. As only, three-cars of a five-car train have them, I may have been in a car without a diesel generator.

Class 800 Trains

The Class 800 and its similar siblings are the nearest we have to an ultimate bi-mode train.

125 mph On Electricity And 100 mph-plus On Diesel

Hitachi’s trains do not yet have the ability to cruise at 125 mph on diesel, but they will get closer in the next few years.

Batteries To Handle Regenerative Braking

I cover this fully in Do Class 800/801/802 Trains Use Batteries For Regenerative Braking?

In the related post,I include this schematic of the traction system.

Note BC which is described as battery charger.

The diagram came from this document on the Hitachi Rail web site, which has the following description.

The system can select the appropriate power source from either the main transformer or the GUs. Also, the size and weight of the system were minimized by designing the power supply converter to be able to work with both power sources. To ensure that the Class 800 and 801 are able to adapt to future changes in operating practices, they both have the same traction system and the rolling stock can be operated as either class by simply adding or removing GUs. On the Class 800, which is intended to run on both electrified and non-electrified track, each traction system has its own GU. On the other hand, the Class 801 is designed only for electrified lines and has one or two GUs depending on the length of the trainset (one GU for trainsets of five to nine cars, two GUs for trainsets of 10 to 12 cars). These GUs supply emergency traction power and auxiliary power in the event of a power outage on the catenary, and as an auxiliary power supply on non-electrified lines where the Class 801 is in service and pulled by a locomotive. This allows the Class 801 to operate on lines it would otherwise not be able to use and provides a backup in the event of a catenary power outage or other problem on the ground systems as well as non-electrified routes in loco-hauled mode.

This is all very comprehensive, but it doesn’t say anything about batteries, except that the auxiliary power supply incorporates a battery charger.

It would appear the batteries might be used to provide emergency power, but the document doesn’t say, if they can be used as traction power.

I suspect that in the next version generator units (GUs), and batteries will work together to make a more efficient train, that can use braking energy for traction.

Using batteries in this way, means that regenerative braking is available in both electric and diesel modes.

Emergency Power

Note how in the above extract, it states this.

On the other hand, the Class 801 is designed only for electrified lines and has one or two GUs depending on the length of the trainset (one GU for trainsets of five to nine cars, two GUs for trainsets of 10 to 12 cars).

This will be very handy for short diversions or when the electrification fails, to get the train to the next station.

Ability To Split And Join Automatically.

This is an extract from the document on the Hitachi Rail web site.

Because the coupling or uncoupling of cars in a trainset occurs during commercial service at an intermediate station, the automatic coupling device is able to perform this operation in less than 2 minutes.

It is fascinating to watch the closely related Class 395 trains do this at Ashford International station.

Plug And Play Trains

The document on the Hitachi Rail web site, explains in detail, how the train’s computer works out what coaches have been coupled together, to create the actual train.

It even automatically adjusts everything if two trains are split or joined together.

Acceptable Noise And Vibration

On my short ride, I didn’t notice the noise of the diesel engine, but on a first look, it appears to be acceptable.

Fast Changeover From Electric To Diesel And Vice-Versa

As I didn’t notice the change to diesel, somewhere past Didcot Parkway station, I must assume, this can be done at line speed.

Conclusion On Class 800 Trains

I feel that the next generation of these trains will be more advanced and efficient, and will be capable of 125 mph on both electrification and diesel.

Routes For 125 mph Bi-Mode Trains

There are several roues, where a 125 mph bi-mode train could be an ideal train to serve the route.

Kings Cross To King’s Lynn

This is a route, that I wouldn’t have thought about, as it is electric-only until I read a short article in Edition 849 of Rail Magazine, which was entitled Call For ETCS On King’s Lynn Route, which advocated the following for the route.

  • 125 mph trains
  • Modern digital signalling, which would include ETCS.

These would increase the capacity South of Hitchin on the East Coast Main Line and make timetabling of the Fen Line much easier.

Then in the next edition of the magazine, there was an article, that advocated the reopening of the King’s Lynn to Hunstanton branch line.

At just fifteen miles this would be ideal for bi-mode trains or ones with sufficient battery capacity.

There are other routes, which feature the following.

  • 125 mph running on a high speed line, which is fully or partly electrified.
  • An extension on a branch line without full electrification.

A few example routes include.

Euston to Chester

Kings Cross to Harrogate

Kings Cross to Hull

Kings Cross to Middlesbrough


Midland Main Line

The new East Midlands franchise for the Midland Main Line will go the 125 mph bi-mode route.

  • The InterCity 125 trains don’t meet the disability regulation after December 2019.
  • No more electrification will be added to the route in the next few years.

The Department for Transport says this in this consultation on their web site, about the new franchise.

The new franchise operator has a key role to play in facilitating the delivery of new infrastructure and delivering the benefits the investment is funding, including the benefits delivered to passengers through a modern fleet of bi-mode trains. Bi-modes will deliver passenger benefits sooner than electrification would without the disruption from putting up wires and masts along the whole route.

But some improvements should be completed by December 2019.

  • The route will be electrified from St. Pancras to Kettering and Corby.
  • The route will be four tracks from St. Pancras to Glendon Junction, where the Corby branch leaves the Midland Main Line.
  • The overhead line equipment South of Bedford will be upgraded to allow 125 mph running.

Bi-mode trains capable of 125 mph, would appear to be a necessity of running the Midland Main Line efficiently.



November 21, 2018 - Posted by | Transport/Travel |


  1. I fully agree with you on Euston-Chester – running a large and heavy diesel train on a largely electrified track is daft – but I’m not sure what the long-term intention is here. The upcoming W Coast Partnership franchise will continue to include Euston-Chester and N Wales, but such trains won’t run on HS2, so once that is fully operational people will presumably have to change at Crewe, so there’ll be no need for bi-modes. Unless the existing trains continue to run on the existing tracks. It would be much more sensible for WCP to run bi-modes (you could conceivably add batteries to Pendolinos for Euston-Chester) rather than Voyagers, but I fear they’ll probably just continue to use the Voyagers. People have until recently assumed that Crewe-Chester and further into N Wales would be electrified, but I doubt now whether that will happen.

    Comment by Peter Robins | November 21, 2018 | Reply

  2. Talgo are the big Spaniard in the Works on routes like Euston and Chester.

    They already make bi-mode trains for running on very high speed lines with unelectrified extensions, like Madrid to Santiago di Compostella.

    As I believe that you can create a 125 mph bi-mode with batteries and smaller diesels, and I think Bombardier have already worked out how to do it, I can see some interesting trains emerging.

    I could see a train capable of 140 mph on much of the East and West Coast Main Lines, that could also attain better times than Voyagers on the current route between Crewe and Holyhead.

    Throw in Talgo’s passive lightweight tilting technology, improve the North Wales Coast Line and I wouldn’t be surprised to see Euston to Holyhead times coming down by about half an hour.

    I also find it interesting, that Talgo are putting a Research Centre at Chesterfield. The UK must be the ideal place to test high speed trains not running on electrified lines.

    I think there’s going to be a serious fight between Bombardier and Talgo to create trains that work well in countries, where there isn’t much electrification; Australia, Canada, India and the United States come to mind, where they all speak English better than what we do!

    Comment by AnonW | November 21, 2018 | Reply

    • That’s an interesting point. I’ve been on the Santiago-Madrid Alvia route, also Barcelona-Pamplona. As someone old enough to remember the lengthy change-over on the old Madrid-Paris trains at Hendaye, the impressive thing there is the ability to change gauge whilst moving. But all the talk I’ve seen for ‘classic compatible’ in Britain has been for extending HS2 on to electrified lines. Primarily Edinburgh/Glasgow, though others like Newcastle and Liverpool can also benefit. I’ve not seen any mention of extending on to non-electrified lines. There’s also the question of what paths are available, and how to deal with delays with connections. The population density in England, and hence the density of rail traffic, and hence the likelihood of delays, is much greater than in Spain.

      Comment by Peter Robins | November 21, 2018 | Reply

  3. I’ve just noticed “DfT suggests that bi-mode trainsets ‘capable of operating at up to 225 km/h in electric mode’ could be used on HS2 infrastructure to support enhanced connectivity between northern cities.” I’ve also seen proposals from Midlands Connect indicating they’re thinking in terms of using HS2 infrastructure for connections between the Midlands and northern cities.

    Comment by Peter Robins | November 21, 2018 | Reply

    • I don’t see why HS2 can’t be used for other services! After all Southeastern use HS1

      Comment by AnonW | November 21, 2018 | Reply

      • true, but then the Javelins just have to cope with different forms of electric supply, something that is only needed in the SE. Adding an on-board power source adds to the weight and presumably the cost, plus there’s more to go wrong. The TGV too runs extensively outside the actual high-speed LGV lines, but I don’t think they have any diesel bi-mode, or any intention to have them. I suppose it boils down to whether the convenience of through trains justifies the cost/extra weight of bi-modes.

        Incidentally, according to the bi-modes are a joint development of Talgo and Bombardier.

        Comment by Peter Robins | November 21, 2018

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