This is Purgatory. It is the Last Train on Earth.
It travels on dilapidated tracks across the remains of a long forgotten civilization.
The train cannot stop.
There is no destination. There is nowhere in this world left to go.
But the train cannot stop.
Not for long, at least. Long enough to forage amidst the wilderness or stop in at automated stations. Just to gather supplies to live another day.
Wherever the train goes, a creeping fog follows. It rolls across the landscape and leaves the land decayed. This fog has already consumed the rest of mankind.
There is no destination. But the train cannot stop.