Passengers said in surveys that they wanted their privacy protected
Sniffer dogs and X-ray equipment will be used to screen some mainline rail and Tube passengers under new security measures being introduced by police.
But ministers have ruled out the use of full airport-style screening as too disruptive, after trials at stations.
British Transport Police (BTP) said the measures - an extension of existing stop-and-search powers - would cause "minimal disruption".
Government surveys showed passengers were unlikely to accept major delays.
Passengers also said they wanted their privacy protected.
BTP said it was enhancing its existing search powers with the use of X-ray equipment for screening bags and deploying more dogs trained to sniff out explosives.
Its existing search measures allow officers to screen a proportion of passengers and their bags "with minimal delay".
Details have yet to been announced about the timescale or location of the new measures.
The plans were released as Transport Minister Tom Harris announced the results of security trials at five Tube and mainline locations in 2006.
He said the trials showed screening equipment and dogs could be effective on the railways.
But given large passenger numbers and thousands of entry points on the UK rail and Underground networks, 100% airport-style screening was not feasible with current technology.
The minister also said the public recognised the security threat to the rail network and was broadly supportive of the need for more measures, as long as they were proportionate.
The government would keep assessing how the new screening was working and keep working on other ways of "keeping the travelling public secure using proportionate measures", he added.
BTP Superintendent Phil Trendall said: "With the use of these X-ray machines and new additional specialist trained search dogs, we are able to screen passengers in a manner that is proportionate to the ongoing security risk and with minimal disruption to their journey.