A union that represents railway staff has announced plans for its members at East Midlands Railway (EMR) to take strike action over "growing safety concerns the company has failed to address".
The RMT union said it had been in dispute with EMR since April following the rollout of the 810 fleet (Aurora), which it said had been operating with a "significant number" of faults.
It said its members planned to take strike action on Saturday 1 August and the following two Saturdays.
An EMR spokesperson said any suggestion that the Hitachi Rail Class 810 fleet did not meet the required safety standards was "incorrect", and added it continued "to engage in discussions with RMT regarding this dispute".
Last week, EMR said reliability and maintenance issues with the new Aurora (Class 810) trains - made by Hitachi Rail - were to blame.
EMR has also outlined "challenges" with both the 810s and the older Class 222s, affecting the toilets, air conditioning and catering equipment.
It added the Class 222 trains had also required "additional maintenance support to accommodate increased running and operational requirements".
The operator first introduced the Aurora trains into passenger service in December, after what EMR said was a three-year delay.
According to the RMT, EMR has been sending trains into service that are "likely to fail and require a full reset which leaves the train with no active safety systems".
The BBC has seen an operational briefing, which informs control, signalling and operations staff about undertaking an Aux Off / Aux On reset on EMR class 810 units - which may be required to recover certain faults.
"The process takes approximately 20 minutes and results in the temporary loss of several safety-critical systems, creating an increased risk of an uncontrolled evacuation and removing the driver's normal means of communication with the signaller," it states.
Eddie Dempsey, RMT general secretary, said RMT reps at EMR had been "extremely patient" and tried to engage with management.
"The company has even put out safety notices with no involvement, consultation or negotiation with our reps who represent those most at risk.
"RMT is demanding that whilst these faults exist and until these trains are shown to be operating properly, they should be taken out of service," he said.
An EMR spokesperson said the Hitachi Rail Class 810 fleet entered passenger service after "successfully completing all required testing and meeting rigorous safety standards".
"We recognise the Class 810 fleet has encountered performance and reliability issues in service and are working with the manufacturer, Hitachi Rail, to resolve these issues as quickly as possible," the spokesperson added.
EMR said the rollout of the new Class 810 fleet would continue "in a controlled manner" throughout the rest of the year and 2027.
A Hitachi Rail spokesperson said: "The Class 810 fleet has been in passenger service with East Midlands Railway since December 2025, and more than a third of the fleet has now been delivered.
"Hitachi Rail continues to work closely with all industry partners during the entry-into-service phase of the Class 810 fleet, implementing improvements and supporting the transition from the existing fleet to new Aurora trains.
"We remain focused on delivering the remainder of the fleet and supporting East Midlands Railway as more new trains enter passenger service. As part of this commitment, we are investing in additional testing activity at Long Marston Rail Innovation Centre to improve fleet introduction and delivery of the remaining trains."
