The Atlas Rail Joiner Sidekick tool makes applying rail joiners a snap. Rail joiners are a necessity for your model railroad layout, but they can be awfully rough on your fingertips when applying them to rail ends. The Joiner Sidekick holds the joiner in place and gives you leverage to easily slide the joiner onto the rail. Works in N, HO and O Scales. The Atlas Rail Joiner Sidekick is part of the extensive line of Atlas HO, N and Z Scale track and accessories.