He is the Senior Curator of Rail Transport and Technology at the National Railway Museum,[1] the author of several books on railway and industrial history, and is active in the steam heritage movement.
Between 2001 and 2004, Coulls was the Curator of Energy at the Museum of Science and Industry in Manchester, moving in 2004 to become Collections Care Manager at Locomotion, The National Railway Museum at Shildon.
[8] He is an expert on the Lowca Engineering Works of Tulk and Ley and Fletcher, Jennings & Co.[9] In 2003, Coulls took on loan a 15-ton road roller, built in 1894 by Aveling and Porter,[10] from Beamish Museum,[11] which he subsequently restored to working order.
He is a past general secretary of the Road Rollers Association[12] and from 2015 to 2019 was Chairman of the National Traction Engine Trust.
[13] In 2019, Coulls was the Lead Curator for the Award-Winning exhibition of model steam locomotives at the National Railway Museum "Brass, Steel and Fire" which then moved on to the Science Museum, London in 2020, running to August 2021.