After the survivors got out of the Subway Station the train eventually broke down - luckily, they conveniently broke down close to a relatively pristine Kingstreet, which the survivors just blatantly assumed originated from the 1930's, hence why it's commonly called 1930's Kingstreet. They tried getting the train to start again as quick as they could, after all - time is of the essence in the apocalypse, and they had no idea if there were zombies near them. Eventually, some impatient survivors got sick of trying to work on the train, and decided to explore the area. What they saw - a once bustling city, with buildings, bridges, surrounded by mountains - was nowhere near as beautiful as the bus they saw at the near the bridge. After having a quick look over it, they determined that, although missing some tyres it can still start and will be a good replacement of their now-forgotten train. All efforts were dedicated to finding some tyres, which, would have been alot easier had the zombies not followed them all the way from the subway to Kingstreet. So, the survivors had to fight of zombies, while getting tires. Not easy, right? On top of that, most of the tyres were in the buildings, meaning they had to cross the bridge, find the tyres and then cross it again, making a huge chokepoint. After some heavy losses the survivors eventuially put all the tyres on the bus and off they were, to their next destination, wherever that may be.