People across Wales are being warned of delays and cancellations ahead of rail strikes at the start of October.
The National Union of Rail, Maritime and Transport Workers (RMT) has announced two days of strike action which will take place on Saturday 1 October and Saturday 8 October, across Network Rail and 15 train operators.
Meanwhile, the train drivers' union ASLEF has announced plans for strike action on Saturday 1 October and Wednesday 5 October.
The Transport Salaried Staffs' Association (TSSA) has also announced strike action of its own on October 1.
Transport for Wales said it was not involved with the industrial action but due to the dispute between unions and Network Rail it would be unable to run a number of services on the network on October 1 and 8.
Some services are likely to be much busier than normal on October 5, TfW added.
Transport for Wales has advised against train travel on October 1 and 8, with a "very limited rail service" operating.
The only services operating will be on the Valley lines and a Cardiff to Newport shuttle, with one train operating hourly in each direction, between 07:30 and 18:30.
No other TfW services across Wales and the Borders network will be able to operate, TfW said.
Meanwhile, rail passengers are advised to only travel if absolutely necessary on Friday 30 September and Friday 7 October, the days before the strike action.
Services could be changed with little notice, the rail operator said.
On Wednesday 5 October - the day of train driver strike action amongst ASLEF members - TfW warned its services are likely to be "extremely busy" due to reduced timetables implemented by other rail operators.
Due to the closure of Birmingham New Street station on that day, services between North Wales and Birmingham International will terminate at Wolverhampton.
Advance ticket holders are entitled to change their journey, with any fees for changing being waived if done so before 18:00 the day before travelling, according to TfW.
Those with anytime, off-peak or advance tickets, also Ranger/Rover tickets, for a TOC on strike – dated for 1, 5 or 8 October are permitted to travel either on the day before the date on the ticket or up to 11 October 2022.
For those who have a return ticket and cannot make their outward journey because of a strike, they are eligible for a refund on their ticket even if the latter is not affected by a strike.
The same applies if the return journey is affected by a strike but the outward was not.
Rail customers can also claim a full refund if their journey is affected and those with season tickets can apply for compensation.