Ride the train rails is a mission in Going Commando taking place in Allgon City, Damosel. Ratchet and Clank decided to ride the train rails in order to look for a shortcut into the city. While they did not find a shortcut, they did find one of the three Hypnomatic parts.
The mission begins by taking the right exit in the first dome, where you will find a grind rail. Hop on the grind rail to begin the mission, and then immediately jump left onto the train that teleports in, and then jump back to the right, jumping left and right as needed to dodge the towers until you reach the rail with the dead end. Jump right before it ends, avoiding the Protopet (or kill it with the OmniWrench) then keep jumping until you reach a long rail that spirals up.
Along this rail, hit the Protopets with the wrench, and jump over the red rings. Then, when near the top, jump over the gaps and you will eventually reach a set of four rails side-by-side with trains driving down along them. Jump onto the rails, and the view will invert (meaning hold the right to jump left, and vice versa), proceed to dodge the trains on time until the view inverts.
The rest of the path is relatively straightforward: avoid the obstacles, kill the Protopets, and jump over gaps. When you get to the top of a large rail spiraling up a tower, it will take a sudden descent down, at the end of which are blue lines for teleporting trains. Jump on the rights, then jump right twice, and left once, to hop onto the platform and obtain the Hypnomatic part, finishing the mission.