More than 100 Hitachi class 800 trains have been withdrawn from service in recent days for safety checks.
Services on key intercity routes, including those operated by Great Western Railway (GWR) and London North Eastern Railway (LNER), have been affected after cracks were discovered in a number of the Azuma trains.
Where are the UK’s Hitachi trains made?
The Hitachi 800 Azuma trains are assembled at the company’s Newton Aycliffe plant in County Durham.
The 43,000 square metre plant was built specifically to allow the assembly of the new trains after a consortium led by Hitachi Rail Europe won the £5.7 billion contract to replace the old intercity stock.
The £82 million plant opened in September 2015 and assembles rolling stock for several key rail network operators, including GWR, LNER, TransPennine Express, Scotrail and Hull Trains.
As well as the class 800 and various derivatives, the plant also constructs the class 383 used by ScotRail between Edinburgh and Glasgow. As a result, trains on that route have also been checked for the same cracking issue.
Why have the trains been withdrawn?
Since Saturday, 8 May, more than 100 Hitachi 800 trains have been temporarily withdrawn from service. These include 93 operated by GWR and 65 operated by LNER.
The trains have been withdrawn after small cracks were detected in the chassis of a number of carriages.
A GWR spokesperson said that the tiny cracks had been found in “multiple” trains so all stock was being inspected as a “precaution”.
Hitachi confirmed that the cracks were found on the lifting points under the carriage of some trains, which are used during maintenance, and it was carrying out inspections on all class 800 trains.
Robert Nisbet, director of nations and regions at industry body the Rail Delivery Group said that while the fault didn’t pose “any particular danger” to passengers it could develop into a more serious issue if left unaddressed.
Hitachi has said that some trains have already been returned to service following inspections but rail operators have warned that the associated disruption could continue for several days.
A Hitachi Rail spokesperson said: “Some Class 800s have been taken out of passenger service as a precautionary measure to allow for thorough investigations.
“We are working with all partners to resolve this issue as quickly and safely as possible.
“We would like to offer our sincerest apologies to passengers for the impact this may be causing for their travel plans.”
The fault is believed to be a separate issue from cracks discovered in suspension elements of the class 800 trains in recent weeks.