The country's biggest rail union is calling for an urgent security summit as it warns staff cuts and the introduction of driver-only trains will increase the terror risks faced by passengers.
The Rail, Maritime and Transport union said train guards are being issued with instructions to make security announcements advising passengers to keep bags and belongings with them and report any suspicious activity to a member of staff or British Transport Police.
The union accused rail companies of seeking to remove guards, as it continues with disputes over staffing on Southern, Arriva Trains North and Merseyrail services.
Strikes planned at all three companies were called off this week because of the Manchester bombing.
RMT general secretary Mick Cash said: "Rail staff are required to follow strict procedures to help reduce the risk of terrorist attacks, but if you remove the guarantee of the guard on trains or cut the number of station staff you will reduce the frequency of the security checks and security announcements that could be vital in preventing a terrorist attack.
"We would hope that there would now be an industry and political consensus to say that we should not be taking guards off trains and staff off our stations.
"We are calling for a summit of politicians, the industry, transport police and unions to ensure that security concerns are put at the forefront of decisions on front-line staffing.
"As well as Government ministers, we would hope that summit would also include the new metro mayor of Liverpool, whose transport authority is trying to get rid of guards, and the metro mayor of Manchester, who will no doubt have concerns that Northern Rail are also attempting to introduce driver-only trains."
The UK's worst train stations
The UK's worst train stations
This Edwardian station was built in the early 1900s and is operated by East Midlands Trains. 59 per cent of people surveyed said they were satisfied with the station - a low score which ranked it bottom for both cleanliness and facilities in the Passenger Focus National Passenger survey.
Birmingham New Street railway station is the largest and busiest serving Birmingham. Despite the regular flow of people, only 64% of passengers surveyed in the National Rail Passenger Survey (NRPS) are satisfied with the sation.
London Bridge railway station is a central London railway station and a London Underground complex in the London Borough of Southwark. The station is the oldest railway station in central London and one of the oldest in the world. 67% of passengers surveyed were satisfied with this station, the fourth busiest station in London.
Peterborough railway station is a major interchange serving both the north-south ECML, as well as East-West long-distance and local services. The station is managed by East Coast. Just 67% of passengers surveyed were satisfied with this station.
Crewe station was completed in 1837 and is one of the most historic railway stations in the world. Like London Bridge and Peterborough, only 67% of passengeres surveyed were happy with this station.
Gatwick Airport station provides a direct rail connection to London. The station platforms are located about 70 metres away from the airport's South Terminal. 69% of passengers surveyed were satisfied with this station.
Stockport railway station was identified as one of the ten worst category B interchange stations by a mystery shopper assessment in 2009. Despite improvements being made to the station since, it is still one of the ten worst stations with only 70% of passengers satisfied with the station.
Clapham Junction station is one of the busiest in Europe by number of trains using it with many routes from London's two busiest termini, London Waterloo and London Victoria. Only 71% of passengers surveyed were satisfied with this busy station.
Maidenhead railway station serves the town of Maidenhead, Berkshire, England. It is served by local services operated by First Great Western from London Paddington to Reading, and is also the junction for the Marlow Branch Line. The survey showed 71 per cent of respondents were satisfied with the overall quality of the station, giving it the ninth lowest satisfaction rating.
Coventry station has the PlusBus scheme where train and bus tickets can be bought together at a saving. Despite this convenient feature, only 72% of passengers surveyed were satisfied with the station.