Strike action has been voted in by drivers at three more train companies.
In a dispute over pay, workers at Chiltern Railways by Arriva, Northern Trains, via the Department for Transport's public sector owning group DOHL, and Transpennine Express, owned by FirstGroup PLC (LSE:FGP), are planning to walk out, though no date has been set.
Rail strikes have already disrupted millions of journeys this summer, with many commuters who cannot work from home and people travelling for leisure during the summer holidays being the most affected.
On August 13, train drivers from the Aslef union walked out at nine operators.
A separate protest by about 40,000 members of the National Union of Rail, Maritime and Transport Workers (RMT) affected 13 train companies and track operator Network Rail.
Staff at 14 train companies and Network Rail were also involved in RMT strikes on July 27, and August 18 and 20.
The TSSA union also walked out on August 18 and 20, describing it as the first multi-operator strike in generations.
"Strikes are always the last resort, but you can see from the votes and turnout just how angry our members are," train drivers' union Aslef was quoted by media as saying.
Mick Whelan, general secretary of Aslef, said train companies should come up with a "proper proposal" to avoid another strike.
A spokesperson for the Rail Delivery Group, which represents train operators, said, "We want to give our people a pay rise", but unions must recognise that as a sector that has lost 20% of its revenues, one must adapt or decline.
"Instead of causing further disruption to passengers and businesses, we urge the Aslef leadership to continue talks so we can change our services to meet new travel patterns, improve punctuality and secure a bright, long-term future for our people."