Multiple reports indicate HS2's top speed could be reduced from the currently planned 360 kph (224 mph) to as low as 300 kph (186 mph) under cost-cutting measures being considered. The originally planned top speed of 360 kph would have made HS2 trains the fastest in the world. Reducing top speeds from 360 kph to 300-320 kph would extend journey times between London and Birmingham by around three to five minutes, from a projected 41 minutes.
Engineering challenges and massive cost overruns are driving the speed reduction considerations. No railway in the UK or globally is currently engineered for speeds as high as 360 kph, requiring a bespoke track for testing that would delay completion and cost billions. HS1, used by Eurostar trains between London and Kent, is engineered for speeds up to 300 kph, allowing HS2 trains to be tested on it if speeds are lowered to that level.
HS2 has spent over £40 billion since 2019 but is only half complete, meaning the London to Birmingham leg alone will likely cost more than £80 billion. The £2 billion order for 54 high-speed trains, to be built in Britain by Alstom and Hitachi, is under review as HS2 Ltd seeks to cut costs and renegotiate contracts. The train order was placed in 2021, before the cancellation of the northern leg of HS2 by Rishi Sunak in 2023.
The original plan for 200m-long eight-carriage units to double into 16-carriage trains will now only be possible on the new line between London and Birmingham, as existing stations like Manchester Piccadilly cannot accommodate 400m-long trains. This creates significant capacity reduction and operational limitations north of Birmingham. Limited to eight carriages, HS2 services will reduce capacity on the conventional railway line north of Birmingham, where current Pendolino trains are faster and longer.
It's a tragedy where we are now.
The Hitachi-Alstom trains would not be able to tilt like Pendolinos, limiting their speed on curved conventional tracks. Chris Gibb, a non-executive director of DfT Operator, warned that if HS2 opened by replacing 11-coach Pendolinos with eight-coach trains, these would be full and leave people behind on day one. Alternative train configuration options are under consideration but come with drawbacks.
An option under consideration is to order about 43 longer trains at 250m-long, which could run to most stations. However, plans to change the size of HS2 trains to maximize capacity are likely to inflate costs and result in fewer seats and slower services north of Birmingham. Gibb warned that varying the train order could pile on extra costs and still leave HS2 unable to match west coast main line fleets.
Warnings have been issued about contract changes and long-term fleet replacement suggestions. Changing the contract would cost time and money, with each potential variation having downsides, including wasting work already done on HS2 stations and depots. Gibb suggested the government should retain the original train order and plan to replace the Pendolino fleet with longer, faster modern versions by around 2040 when HS2 services start running to the north.
Lord McLoughlin, the former transport secretary, questioned whether Gibb's plan would also incur significant costs. For context, the fastest current route between London and Birmingham with Avanti West Coast is around 75 minutes.