If you go near the cylinders, you can sometimes find the handling machines that spawn with them. The tripods do pick you up when they're in the collection stage, although you'll want to wait around 3 days in the 14 day survival mode to see this. Cannons also spawn, but simply as semi-random objects that fire at the tripods, I don't believe they actually do anything.
Viewing post in War of the Worlds (Legacy Version) comments
The current build, they're pretty buggy, and sometimes seem to not spawn (maybe fall out of the map), but they're there. Be careful though, as if they're not stuck on the terrain they'll move towards you, and kill you on contact. Just look around old cylinder crash sites, they don't stray too far from them. (You can find martians outside of machines around too.) When the virus kicks in all non-tripod martians instantly die, and the tripods die soon after thanks to the "sick" stage.