Are standards for the railway too rigid?

Maybe. A case study on door operation.

Sometimes, it is worthwhile to re-examine your standards. Is your use of standards too rigid? Are you locking yourself into over engineering your railway? Are you sticking to the rules because they are the rules? Are there opportunities to gain time, reduce costs, improve visual impact or upgrade the passenger experience by adjusting standards, re-analysing risk or getting a derogation? This article offers a small but important example of how a standard could be modified to good effect.

This case study, first written in 2018 expressing concern about the rigid use of standards, is on train door operation. If we assume door opening is activated by a member of the train crew, we would want to ensure that the doors remain closed until the train has stopped. Once wheel stop (zero speed confirmed) has been detected, the on-board system can unlock the door opening controller and the crew member can release or open the doors.

Waiting for Doors

Fine? Yes, as far as it goes. It is definitely safe but this arrangement causes a considerable lag between wheel stop and door opening. Time is needed for wheel stop to be detected, for a release indication in the cab to appear, for the train crew to operate the release buttons, for the door controllers to receive the signal and for the doors to begin opening. On many main line trains, it can be 7-8 seconds before the doors are opened for passengers. On a metro or suburban service, it can be 3-4 seconds. An extra four seconds at every station on a line like the London Overground route between West Croydon and Highbury & Islington adds 76 seconds to the train’s journey time. This is half a train path and buying a peak-hour train path is expensive, so both time and money are being wasted. Perhaps there's a better approach? Perhaps we could use human experience to inform automated system protection?

In the days of guard door operation on the London Underground (finally abolished in 2000), there was no interlocking of doors with train movement. Doors could be opened while the train was moving. They weren’t of course (usually) but the facility was used to speed up station operation. The experienced guard knew that there was always going to be a lag between the train wheels stopping and the doors opening fully and he knew also that station stop time had to be kept to a minimum. To keep dwell time short, the guard would press the door open buttons a second or two before the train stopped so that the doors were beginning to open at wheel stop. Valuable seconds were saved and no one got hurt. So, why can't we replicate this in an automated system?

Speed Detection

Could human experience be replicated in automation? Of course it could. It fact, it already has. In January 1980, the first D Stock train went into service on the District line with a new door control system that kept the train door control locked while the train was moving but which allowed the guard to release the doors if train speed was detected below 4 mph. It replicated the human experience that allowed time to be saved at stations. It remained in use for many years but the idea was lost in the safety panic that ensued after the Kings Cross fire of 1987. Perhaps, now, with efficient train throughput at the top of the railway agenda, is the time to review the rigid zero speed restriction on door opening and make better use of the technology available for the digital railway. And, are there other examples where this approach could be beneficial?

Timetables and Control - Thameslink Case Study

Silence is Broken

Back in the Summer of 2018, I watched the continued disruption to the train services operated by Govia Thameslink Railway (GTR) with dismay and despair. I thought, after three weeks of operation following the introduction of a new timetable in May 2018, they would have got it sorted out, at least to a level where some sort of regular and reliable train service could be operated. But they haven’t. There we were, in the 6th week of the new timetable and there were still serious problems with the train service.

Why three weeks to get it sorted? Because, if you consider the average 24-hour shift pattern of early, late and nights, spread over three weeks of operations, it should allow most of the core staff to get used to the new pattern of services, the new train crew duties and the new routes. But it hasn’t happened like that.

Silence

I’ve stayed silent for a while as I thought I couldn’t add anything useful to the huge range of complaints, blame, calls for the stripping of “franchises” and largely uninformed nonsense from the popular press and social media. In vain, I waited for some sensible comments asking some basic questions about how the service was planned and how it was controlled on a day by day basis but none came. I waited in vain for a proper analysis of the issues and solutions but there were none. So I’ve decided to break my silence and offer some basic ideas, based on my own experience of timetable preparation in various places around the world and of train service operations.

The Routes

The Thameslink routes are too complex. The old setup with a Bedford to Brighton main line with the Sutton loop tacked on was quite complex enough, without adding such destinations as Peterborough and Cambridge in the north and Orpington, Sevenoaks, Horsham, Rainham, Littlehampton and East Grinstead in the south. In the originally planned December 2019 timetable, they were going to add Kings Lynn and Ashford too. This would not work well.

Battery-Electric Trains

Why Battery Electric?

Why?  Decarbonisation of course. The advances in battery technology, driven by the automobile and computer industries are now showing real benefits for the railway business. Batteries for traction are now a reality and are gradually entering mainstream. They are offering a way of decarbonising railway operations by replacing diesel traction with battery traction. 

Unlike a conventional electric train, a battery-electric train can operate without a continuous overhead wire or electrified third rail. It can replace a conventional diesel train, on a route without electrification. Full electrification is very expensive. It can cost up to £2 million per track kilometre. Being able to use a train with a battery offers the opportunity to decarbonise the railway without the expense overhead electrification. Battery electric trains need a rapid charging system but this can be provided at a terminus so the train can recharge while it's waiting for its next trip.

A diagram of the trial on the Great Western Railway using a former London Underground D Stock train as a battery electric multiple unit (BEMU). The recharging system uses track mounted rails to recharge the train rather than an overhead supply. Photo: GWR.

A feature of modern traction systems is that a train equipped with electric motors can use these for braking. During braking, the motor becomes a generator and the current produced can be fed back into the overhead line system on an electrified line or back into an on-board battery, if the vehicle has one. This 'regeneration' can be used to recharge the battery while the train is in service.

Challenges

However, the system is not without its challenges. After a long period of gestation, battery-electric trains are now being more widely recognised as a way to decarbonise the railway at a reasonable cost. We can define a battery-electric train as a railway vehicle that stores traction energy in rechargeable batteries and uses it to power electric traction motors.

The engineering challenge is to integrate energy storage, traction, braking, thermal management, structural design and system safety into a vehicle that can carry its own rechargeable batteries, recharge them en route and complete its journey on a finite battery charge. It also has to provide a viable and safe system of battery recharging and the electrical supply system to operate it. None of this will be easy.

Stadler 3-car Battery-Electric Multiple Unit (BEMU) Photo: Stadler.

In general terms, the engineering challenge is to ensure that the train has sufficient energy, power, range, acceleration and braking capability while remaining safe, reliable, maintainable and economical throughout its service life. For BEMUs, the jury is still out. They haven't been around long enough to see a whole life. However, the signs are promising with every increasing improvements in battery life and recharge ability.

Progress

BEMU trains first appeared in passenger service in Germany in 2020. They arrived after a long gestation period, but they pointed the way ahead. In the UK in February 2015, a battery-fitted Class 379 Electrostar unit began in trials on the Harwich branch. This was the first battery-powered train in the UK. It ran on battery power up to 77 kms. 

Some serious experiments began with the conversion of some former London Underground district line trains, known as D stock and now designated Class 230, that were converted for battery operation. Although a few are in use around the country, the conversion is expensive and the reliability is poor. Conversion of old equipment is always difficult. New builds have proved to be better.

The first purpose-built battery powered passenger train entered service on the extension from Kirkby to Headbolt Lane on 7 October 2023. More recently, Rail Operations Group’s Class 93 locomotives feat Scotture a battery pack as well as diesel power and 25kV overhead line operation and Hitachi tested a tri-mode conversion of a TransPennine Express Inter-City unit train with a battery pack in place of a diesel generator on one car. A fleet of 29 new BEMUs have been ordered for the Trans-Pennine route as a result.

TransPennine Express have ordered 29 new BEMU trains from Alstom. They will be built at the Litchurch Lane Works in Derby, They aren't expected to enter service until 2034. Photo: TPU

In London, the new 2024 Stock Piccadilly line trains (currently in pre-service testing) have a battery ‘get to the next station’ facility. In Birmingham, some of the CAF trams have batteries added to allow them to serve an extension of the system to Edgbaston Village. All of these are hybrid trains or trams and we can be sure that there will be more to come.

More information:

Battery electric and battery hybrid trains, Rail Engineer, June 2024.

Batteries Included, Rail Engineer August 2025