More than 160 passengers had to be ejected from a train heading towards Northampton because they were classed as "not fit to travel."
In addition, 26 penalty fares were issued to people travelling on the 00.34 Euston–Northampton service on Friday night (January 20) without tickets.
London Midland has been deploying extra security on certain trains in recent weeks based on feedback from customers and frontline staff.
Darren Hanley, head of revenue protection & security, said: “Quite frankly these people were not fit to travel.
“We have implemented this initiative following direct feedback from what our staff and customers are telling us. This particular service needed action taking and we have invested in measures and solutions that will ensure the safety and welfare of all of those on board our service.
“Our staff should not be coming to work to face harassment, likewise, passengers shouldn’t be put in harm’s way and this initiative will directly improve the environment for all on board.”
Steve Helfet, head of west coast services at London Midland, said: “The safety and welfare of our customers and colleagues is our number one priority and we will do all we can to ensure that passengers feel safe and our team has the support they need.
“It is the few that spoil it for the many and our goal is to stamp this out with immediate effect – these early results are a step in the right direction.”
In addition to the 162 stopped from travelling on the, 26 Penalty Fares were issued to people travelling without tickets.