Railroad maker Hitachi Rail has apologized to passengers and promised to conduct a thorough investigation after numerous micro-cracks were found on the hulls of high-speed trains, leading to a halt in rail links between several regions in the UK.
Passengers on trains in the east and west of the country are currently experiencing delays and cancellations.
The issue has been reported on Hitachi 800 class trains used by rail companies including London North East Railway (LNER), Great Western Railway (GWR), Transpennine Express and Hull Trains.
Trains are built at the Hitachi Train Assembly Plant in Newton-Aycliffe, County Durham.
Hitachi Trains CEO Andrew Barr confirmed that the decision to decommission the Hitachi 800 trains was caused by cracks found in the metal connecting the train body to the bottom of the train.
Mr Barr did not give the exact number of trains stopped - stating that the situation has not yet been resolved - but indicated that additional cracks were found in several trains in addition to those originally discovered.
He said the cracks could not be seen with the naked eye and were originally discovered during routine maintenance. It has not yet been announced where the steel used to make the train bodies was made.