Call of Duty: Warzon's rip-roaring success has been impressive to behold, and be part of as a player, but it's fair to say that any battle royale game needs content injections to stay fresh.

• Call of Duty Warzone tips and tricks: Essential hints to dominate Season 4 of the COD battle royale

In Warzone's case, as with other behemoths like Fortnite, that means a seasonal structure that sees changes drop at the start of each new wave, along with a new Battle Pass for players to churn through.

Season 4 is in its twilight days, now, with a couple of weeks before the pass ends, and 5 August is being bandied about a lot online as the likely launch date for the next Season. The big headline addition, as far as anyone can work out from the teasers being dripped out? A train. 

Now, that's actually more exciting than it sounds - over the last couple of months Infinity Ward has been quietly, without announcing anything, been adding more train tracks and tunnels to the Verdansk map, connecting up a loop of track that can now run a circuit around the whole place. 

A teaser video freshly sent to Call of Duty streamer NICKMERCS has added serious smoke to the fire of this rumour, too, as you'll see below.

It makes sense, then, that it's planning to put something on that loop, and a moving train with high-value loot could be a perfect way to entice players into new strategies and tactics. 

There's also an abiding expectation that the Stadium which takes up a decent chunk of map right near its centre might open up and become more of a traversable area instead of being the preserve of helicopter pilots. 

Regardless, we can't wait for Season 5 to drop - changes substantial enough to mutate how the map plays are key at this stage, especially with a new map looking like a remote possibility for now.