The strikes are set to affect travel to the London Marathon.
The union said it had successfully negotiated pay deals with nine train companies this year, but remained in dispute with some firms which it claimed hadn't offered any deal and where drivers hadn't had a pay increase since 2019.
"The companies with whom we are in dispute have not offered us a penny. It is outrageous that they expect us to put up with a real terms pay cut for a third year in a row. And that's why we are going on strike."The Rail Delivery Group, which represents train companies, said the strikes were "not in the long-term interests of rail workers or building a sustainable rail industry.
The BBC understands other rail workers such as guards and signalling staff who are members of the RMT Union, will also take part in another day of industrial action on 1 October. A series of large-scale rail strikes has already happened in recent months, causing disruption for millions, with unions wanting pay increases in line with the rising cost of living.