document: Rail union RMT said it was speaking to its 523 members over plans to hire security contractors on the company's trains.
  London Midland told the union it stopped using contractors last month.
  RMT said the decision was "a major victory", while London Midland said it was pleased passengers would not be affected by "unnecessary" strikes.
  More updates on this and other stories from Birmingham and the Black Country.
  The union said its national executive committee decided to cancel the strike ballot and end the dispute after receiving "written assurances" from London Midland the use of contractors would stop after 30 January.
  General secretary Mick Cash said train security and passenger safety was only possible with "professionally trained and equipped" employers and "an adequate number of conductors.
  "RMT remains eternally vigilant in the ongoing fight to stop the casualisation of rail workers' jobs and any moves that undermine permanent staffing arrangements," he said.
  A spokesman for London Midland said it "decided to review our current arrangements" after speaking to staff.
  "We all share the same objectives of improving safety and reducing ticketless travel," they said.
  "Our focus now is to work together on how best to achieve this."
summary: Train conductors have called off balloting for strike action on London Midland's service.