'Hell on Wheels' Ratings Take a Hit Without 'Walking Dead' Lead

The second season premiere of AMC's Western is down by nearly two million viewers from its robust 2011 debut.

Hell on Wheels kicked off its sophomore season on Sunday night, shifting to 9 p.m. ET and losing its Walking Dead lead in the process.

The episode brought in 2.5 million viewers, 793,000 of them adults 18-49 (a 0.6 rating). It's a dramatic drop from the November 2011 premiere, the second-highest in AMC history, which drew 4.3 million viewers and 2.4 million adults 18-49 (a 1.9 rating).

But it's also not that far south of numbers achieved during January's freshman ender. That episode pulled in 2.9 million viewers and a 0.7 rating with adults 18-49.

The ratings are still good for AMC. They top almost the entire run of The Killing by a wide margin and are on par -- at least among total viewers -- with the current run of Breaking Bad.

Hell on Wheels stars Anson Mount and was created by brothers Joe and Tony Gayton. It was renewed for a second season in December.