Around 2,500 members of the TSSA, including inspectors, will walk out on August 18 and 20 – the same days as RMT members – although those in management ranks, who provide emergency staff to continue to services work, will not strike. Members of the Unite union who work as electrical control room managers for Network Rail will also strike on the same days. The TSSA had already called strikes on those dates at seven train operators, following votes last month, but had earlier refrained from striking at Network Rail. However, the union changed its position after it said it had not received clear assurances about job security and working practices. The secretary general, Manuel Cortes, said the strike would have a huge impact. He said: “Our members are just asking for basic fair treatment: not to be fired from their jobs, a fair pay rise in the face of a cost of living crisis and no race to the bottom on terms and conditions. “No one takes a strike lightly, but we are left with few options. Our general grades and testers are a force to be reckoned with. Without them the rail network doesn’t work, it’s that simple.” Network Rail sources said contingency plans remain in place for now, meaning some trains are likely to run again during the strikes. Subscribe to First Edition, our free daily newsletter – every morning at 7am. BST Unite said its members, who are responsible for managing and controlling the power supply on the rail network, had not received a pay rise for three years. Unite general secretary Sharon Graham said they had “played a critical role in keeping the rail network running throughout the pandemic” and the pay offer they had now received was “a kick in the teeth”. Tim Shoveller, Network Rail’s chief negotiator, said: “We are doing everything we can to avoid disruption to our passengers later this month, but it appears that our unions are coordinating their strike action to maximize the impact on the 18th and 20th August. “We urge all our unions to work with us to agree a deal that is fair to their members – our employees – and affordable for taxpayers and passengers, and we believe it is right that members have a say in the offers which we have done. “ The cumulative strikes, along with action by members of the Rail, Shipping and Transport (RMT) union at 14 rail operators – and a 24-hour RMT strike on London Underground on August 19 – will mean three days of transport chaos. On previous strike dates, about 20% of trains were running between 7 a.m. and 7 p.m. Train drivers belonging to the Aslef union will strike again for 24 hours on August 13.