Thousands more railway workers are to e balloted for strikes in escalating disputes which threaten travel chaos over the summer.

It comes as the Transport Salaried Staffs Association (TSSA) has served notice to ballot more than 6,000 staff at Network Rail (NR) in a dispute over pay, conditions and job security.

READ MORE: Rail Strike: See the dates for all rail strikes

Currently, members of the Rail, Maritime and Transport (RMT) union at NR and 13 train operators are to strike for three days next week in similar disputes which is expected to cause huge disruption to services. 

Plus, the RMT and Unite are also striking on London Underground on June 21, the same day as the first rail strike, in a separate row over jobs and pay.

News Shopper: Thousands more rail staff to be balloted over strike action. (PA)Thousands more rail staff to be balloted over strike action. (PA) (Image: PA)

Previously, the TSSA announced strike ballots among its members at four rail companies – Avanti West Coast, CrossCountry, East Midlands and West Midlands Trains.

Members of the drivers union Aslef are also striking later this month at Hull Trains, Greater Anglia and Croydon Tramlink.

TSSA members at NR work in operational, control, management, and safety-critical roles on rail services across Britain.

TSSA is demanding a guarantee of no compulsory redundancies for 2022, no un-agreed changes to terms and conditions, and a pay increase that reflects the rising cost of living.

The union said NR staff last had a pay rise between two and three years ago (varies between grades) and also worked throughout the coronavirus pandemic as key workers.

Members are being asked to cast two votes: one on strike action and another on action short of a strike.

The ballot opens on June 20 and closes on July 11.

And in the event of a yes vote, strike action could be held from July 25.