Good evening all. I recently visited London once again, this time on a rather special occasion. I went to witness the opening of the central core section of Crossrail on May 24. But what did that sentence just mean? What is Crossrail and why is it not called that officially? What is its central core? Let’s take a look.

London’s newest railway

The term “Crossrail” first came about in the 1970s, for a proposal of a new east to west railway running through central London. After several proposals, construction eventually began in 2009, and after countless delays spanning many years, we got what Transport for London (TfL) calls the Elizabeth line.

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The Elizabeth line links 41 stations, 10 of which are newly built. The central core runs from Abbey Wood to Paddington, and is currently served by 12 trains per hour, Monday to Saturday, 6:30 to 22:00. The outer branches were taken over from regional operators prior to the opening of the core, and have been upgraded in quality to a level one would expect from TfL.

The eastern section

The Eastern Counties railway was opened in 1839, linking a temporary terminus at Devonshire street in East London to Romford. The line extended in both directions, serving many towns in Essex and Anglia, and the current terminus at Liverpool Street opened in 1874, eventually becoming known as the Great Eastern Main Line. Commuter trains operated between Liverpool Street and Shenfield, 33 km to the east. In 2015, TfL took over operations of several commuter services from Greater Anglia, the franchise operator on both the Great Eastern and also the West Anglia main lines, the service to Shenfield being one of them. While services on the West Anglia Main Line were integrated to the London Overground, the line to Shenfield got branded as TfL Rail. This was the proto-Crossrail, as this service was destined to become the eastern section of today’s Elizabeth line.

This video by citytransportinfo explains the changes to the Greater Anglia franchise in May 2015.

TfL Rail inherited a fleet of aging Class 315 electric multiple units. Obviously these were unsuitable for serving high density routes in Central London. New Class 345 trains had been ordered for the Elizabeth line, but due to delays in their construction as well as teething problems after delivery, the trains did not enter service until 2017. In terms of infrastructure, the eastern section is a relatively standard railway, with speed limits up to 100 mph (160 km/h), 25 kV 50 Hz electrification by overhead line. As for signalling, Automatic Warning System (AWS) is used, in combination with Train Protection & Warning System (TPWS). These systems are used almost universally across UK, with AWS being used to provide a simple warning to drivers when needed, and TPWS being used to stop the train in emergencies should the train be going too fast at certain points. AWS+TPWS are relatively simple to implement compared to other signalling systems in Crossrail, such as the newly-implemented European Train Control System (ETCS) on the western section.

The western section

The Great Western Main Line was opened in 1841, running between the terminus at London Paddington to the city of Bristol. The line was engineered by Isambard Kingdom Brunel, who was a proper railwayman. The track gauge was at 7 feet (2140 mm), much wider than the railways today at 1435 mm, and the alignment was so level and straight it was nicknamed “Brunel’s billiard table”. This allowed better stability and as a result of this the line was superb for high speed trains, even after it was converted to standard gauge. Because of high speed limits of 125 mph (201 km/h), the line was fitted with Automatic Train Protection (ATP) starting from 1990. However, for most of its lifetime, the line was unelectrified, and therefore services were operated by diesel multiple units. In 1998, the branch from Hayes & Harlington station to Heathrow Airport opened, and as a result, 25 kV 50 Hz overhead line was provided from Heathrow to Paddington.

Class 360 train. Hugh Llewelyn, CC BY-SA 2.0, via Wikimedia Commons

Two new services emerged from this new branch line: Heathrow Express running nonstop from Paddington to Heathrow with Class 332 trains, and Heathrow Connect, a stopping service using Class 360 trains. The tunnels to Heathrow were fitted with the same type of ATP as the main lines to ensure safety. It should also be noted that the line had always been fitted with AWS, which was supplemented with TPWS as well. Most of the slow commuter trains on the line used AWS+TPWS, whereas high speed trains used ATP. Class 332 trains used ATP exclusively, but had AWS fitted due to a regulatory requirement, without TPWS. Class 360 trains had ATP as well as AWS+TPWS.

GWR’s Clas 387 at Reading. By Geof Sheppard – Own work, CC BY-SA 4.0,

If you’ve been paying attention so far, you have noticed that I’ve typed two whole paragraphs without even mentioning Crossrail. That is because these complex signalling systems were a significant challenge with the introduction of Crossrail services. TfL took over the Heathrow Connect service in 2018, rebranding it as TfL Rail, but continuing to run Class 360 trains to Heathrow. By that point, the Great Western Main Line had undergone a significant improvement programme itself, which included electrification beyond Heathrow Junction, allowing the franchise operator Great Western Railway (owned by FirstGroup, and not be confused with the 19th century railway company who built the line) to run commuter services with relatively new Class 387 units. TfL Rail took over some of them too, specifically as far as Reading, in late 2019, this time using their own fleet of trains.

The trains

Crossrail services today are all operated by Class 345 electric multiple units. The 345 designation was reserved specifically for the Crossrail train decades before any work had started. The trains themselves are a part of Bombardier’s Aventra family, the successor to the venerable Electrostar family, have a top speed of 90 mph (145 km/h), and support AWS+TPWS, ETCS and CBTC signalling. Communications-based train control (CBTC) is a term used to describe many proprietary implementations of signalling used for metro lines, and this was implemented in the central section of Crossrail using the Siemens TrainGuard product. European Train Control System (ETCS) could have been used to provide the same effect, but because work on Crossrail had begun before the ETCS specification was finalised, they were granted an exemption from the rule that requires all new lines to use it. Instead, as the Great Western Line was also undergoing a resignalling programme at the time, ETCS was to be used on the western section. AWS+TPWS was installed for operations on other existing lines.

Class 345 train at Paddington

As with all modern technology, this multitude of signalling systems required complex software to operate. And that software was rather problematic when the trains were first delivered. Thus, as the first Class 345 train was introduced to the eastern section in June 2017 and was shortened to 7 cars from 9 because of short platforms at Liverpool Street, it was decided to use a simpler version of software, designed to only work on existing infrastructure. All 7 car trains were to use this software while 9 car units awaited software updates to enable the advanced signalling systems. This wasn’t an issue in the eastern section, as AWS+TPWS worked perfectly with the simplified software, and so Class 345 units began to replace the old Class 315 fleet on the entirety of the route.

Class 345 at Stratford

However, the western section caused a great deal of problems, specifically because of the Heathrow tunnel and ATP. Because ATP was considered obsolete, the Class 345 fleet wasn’t fitted with it. A decision had been made to install ETCS into the Heathrow tunnel, and this was relatively hassle-free, because it was a short section that didn’t interface with other lines. However, by the time TfL took over Heathrow Connect, Class 345s still faced software issues, which prevented them from running into the Heathrow tunnel. Regulations saw AWS+TPWS as a degradation in safety from ATP, so any service to the tunnels required ETCS to be functional. TfL were able to run 7 car trains as far as Hayes & Harlington, the final stop before Heathrow junction, but this came at the cost of reduced service to Heathrow, terminal 4 now only getting 2 trains per hour instead of the usual 4. Only by May 2020 had the software reached a state where 9-car Class 345 trains could serve Heathrow Airport. The provision of ETCS in the Heathrow tunnels also paved the way for replacement of the old Class 332 Heathrow Express fleet with the freed-up Class 387 trains from GWR, following TfL’s takeover of stopping services to Reading. The Class 332 were the first class of train to be scrapped which was ordered after the privatisation of British Rail, the lack of TPWS made them unsuitable for operation elsewhere on the UK rail network. As for the Class 360 fleet that previously operated Heathrow Connect services, they were reallocated to East Midlands Trains for their newly electrified line.

Class 345 at Heathrow Terminals 2&3.

The big day

All my time in the UK rail scene has led up to the opening of this railway. From the procurement process of the trains that saved Bombardier’s manufacturing plant in Derby, to the first announced opening date of December 8 2018 and all the delays that followed when it became clear that this date would not be met, I have been following the progress of this railway. The last transport project in London that I can think of that had such scale and complexity would be the construction of the initial Jubilee line, which opened in 1979. And so, when the opening date was finally announced, I immediately bought plane tickets to go see it on its first day. In the early morning of May 23rd I left Tallinn Airport for Warsaw, where I would connect to my flight to London Heathrow Airport. The day after that was the big day, and even though I got to Paddington 30 minutes before the first train was due to leave, a crowd had already gathered.

And it was absolutely amazing. I didn’t get on the first train at 6:33, but I did get on the second train 5 minutes later, which wasn’t crowded at all. It was immediately clear that this was not a mere tube line: these are real, mainline trains, running at mainline speeds and providing mainline service. The Class 345 trains are 205m long, both longer and wider than anything on the Underground, and faster as well. It’s also much quieter than anywhere on the tube. The stations are also very spacious, the sheer volume of them isn’t something that can be seen from pictures or videos. Anyway, here are some pictures.

Was it worth taking a week off from work just to watch some trains and stations? Absolutely. The Elizabeth line, as TfL now calls Crossrail, will truly transform transit in London. Does this mark the beginning of an era where other cities in the UK see more investment in transit, or the end of the “silver age” of transit in the UK, one cannot know.

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