"There needs to be rail police - they are the only ones who can really stop things and really stop these kinds of people getting on board these trains."
Reeves said he had concerns about passenger and staff safety on the rail network ahead of tonight's Christmas in the Park at Auckland Domain.
"Let's just hope this is not a precursor for the big event tonight, where they tend to have a lot of issues on the rail network," he said. "I certainly hope the rail network is flooded with police tonight."
A group of teenagers caused mayhem when they smashed windows on a train on the Southern Line in South Auckland last night at about 10pm.
The train's passengers had to be dropped off at Puhinui Station because the train was "munted" Reeves said.
A police spokesman said they were called to a disorder incident in Manurewa East involving a group of male and female teenagers.
"Police were told people had thrown rocks at a train and had then run off," he said.
"Police were told the group had been ejected from the train, and then proceeded to throw rocks at the train.
"The train stopped at Te Mahia station for the crew to check for damage."
A police unit attended and conducted area patrols, he said, but no offenders were located.
"Auckland Transport will assess any CCTV footage and liaise with police if offenders can be identified."
Reeves said a group of youths got on the train at Papakura and allegedly assaulted the Maori warden and train manager.
The manager stopped the train at Te Mahia Station and kicked the youths off.
They then picked up rocks and hurled them at the windscreen, shattering it in three places, Reeves said.
The train engineer then dropped passengers off at Puhinui Station.
"It sounds like this group have thought 'let's get on the train and cause mayhem'," Reeves said.
A spokesman for Auckland Transport confirmed a Maori warden got onto a train at Te Mahia and spoke to a group of 12 youths.
"The group became abusive and when asked to leave they pushed the warden," he said. "Another passenger helped the warden and got the group off the train.
"The group then threw rocks at the front windscreen of the train smashing part of it. The Warden was not injured, and no train staff were involved in any assault."
In the second incident, an Onehunga-Britomart train was stopped at Penrose Station after youths again pushed the emergency stop button, and also tagged the train and allegedly abused the train manager.
