Two customer help points have been stolen from stations on the Severn Beach rail line in Bristol.
The computerised machines were removed from Redland and Montpelier stations.
They provide passengers with the latest travel information and can also be used in an emergency to raise an alarm.
Sgt Mark Harris, from British Transport Police, urged anyone with information about the missing machines to contact police.
He said: "They could be your lifeline if an emergency takes place on the railway or at your station so it is vital they are located and replaced."
Richard Morrish, from First Great Western, said: "The customer help points are of no use to anyone outside the rail industry.
"However these machines do help people within the community and it's a shame that the minority have to ruin things for the majority in this way."
They were taken between 25 and 28 February.