Fewer trains to avoid heat problems
Train passengers will find fewer trains running on Friday afternoon because operator NS wants to avoid problems caused by the heat.
The NS will run a preventative timetable, as it did during the winter, with two trains an hour on busy lines rather than the usual four.
Running fewer trains means problems in one part of the network should not lead to delays elsewhere.
The intense heat on Friday afternoon - forecasts are for up to 37 degrees Celsius - is likely to cause metal points to swell and overhead electricity lines to fail.