'The Big Bang Theory' season 10 episode 15 spoilers, news: Leonard and Howard try to get Sheldon preoccupied; renewal for 11th season still unconfirmed

Leonard (Johnny Galecki) and Howard (Simon Helberg) will try to get Sheldon (Jim Parsons) really busy so that they could work on their invention. Meanwhile, there are still no updates whether the cast of "The Big Bang Theory" has signed on to continue with a new season.

In the upcoming 15th episode of "The Big Bang Theory" season 10, titled "The Locomotion Reverberation," Leonard and Howard will try to keep Sheldon preoccupied by giving him the ultimate gift.

The episode's synopsis reads, "Leonard and Wolowitz try to distract Sheldon when he slows the progress of their guidance system. Also, Penny (Kaley Cuoco) and Amy (Mayim Bialik) take Bernadette (Melissa Rauch) out for the night, leaving Raj (Kunal Nayyar) and Stuart (Kevin Sussman) to care for baby Halley.

As seen from the episode promo, it appears that Leonard and Howard will be giving Sheldon a train that will, later on, trigger Sheldon's crazy quirks.

There are speculations that Sheldon will find out Leonard and Howard's true intentions, which will make him feel bad about himself and his friends.

Meanwhile, it will be Bernadette's first night out since she carried Halley in her tummy. Penny and Amy will make sure that Bernie enjoys her night out while Raj and Stewart watch over the baby.

Only a few episodes remain for season 10, yet there is still no confirmation whether the cast members are returning for "The Big Bang Theory" season 11.

The Hollywood Reporter confirmed that all the cast members are asking for a raise during negotiations for a new contract, but CBS Entertainment and the showrunners remain confident that "The Big Bang Theory" will be renewed for another season.

"The Big Bang Theory" season 10 airs every Thursday at 8 p.m. ET on CBS.