CBS | 8:00 pm
With Sheldon (Jim Parsons) interfering with their work on the guidance system. Leonard and Wolowitz (Johnny Galecki, Simon Helberg) scheme to divert his attention by treating him to a railway trek in "The Locomotion Reverberation." Raj and Stuart (Kunal Nayyar, guest star Kevin Sussman) play babysitters when Penny and Amy (Kaley Cuoco, Mayim Bialik) give Bernadette (Melissa Rauch) a night on the town. Dean Norris also reprises his guest role.