The document summarizes a Rail Accident Investigation Branch (RAIB) report on a collision between a stoneblower and a ballast regulator at Arley in Warwickshire in 2012. The stoneblower was traveling too fast to avoid hitting the stationary regulator. Contributing factors included changes made to the worksite arrangements, the use of long worksites which encourage speeding, and possible driver distraction. As a result of the investigation, the contractor Harsco Rail revised its driving policy to prohibit mobile phone use while driving and clarify speed limits and communication of worksite arrangements for possession work.