The Time Tunnel (1966)

S1E3 End of the World

Dony and Toug find themselves in the year 1910, where a small town is gripped by fear over the impending arrival of Halley's Comet. Tony becomes trapped in a cave-in with around two hundred miners, while Doug struggles to persuade superintendent Henderson to take action, as he believes the comet will spell disaster. Undeterred, Doug rescues Tony on his own and seeks to calm the panic caused by local astronomer Ainsley. As Tony organizes a rescue, the Project team attempts to send Doug a radioscope through the Tunnel. When that fails, Doug constructs a basic radioscope to demonstrate to Ainsley how the comet's gravitational forces will change its path. With Ainsley’s help, the townsfolk rally together to save the miners. Meanwhile, the Tunnel begins to draw in Halley's Comet, narrowly avoiding pulling Jerry in before the team can shut it down.