The Short Answer
Clear the Blue Tower — the fourth and final tower in the recommended Red → Green → Yellow → Blue order. Finishing it unlocks the Monorail train system, which is the last of the four tower travel rewards.
What the Train Actually Is
The world features three-coloured trains — red, yellow and green — that correspond to three coloured stations ("red train, yellow train, green train"). They're a primary way to move around the island once available.
There's a known open question: sources describe both a "Monorail" (the Blue Tower unlock) and separate red/yellow/green trains seen in gameplay. These may be the same system viewed differently, or two distinct travel methods. This is to be confirmed via a full playthrough video and is not yet resolved.
Why Save Blue for Last
The same community guide that ranks the tunnels as fastest calls the monorail slow and infrequent ("pretty unhelpful"). That's exactly why the recommended order does Blue last: by the time you've got the map, chairlift and tunnels, the train is a nice-to-have rather than a necessity.
Working With the Other Systems
- Tunnels (Yellow Tower) — fastest point-to-point travel.
- Cable Car (Green Tower) — required for the east-ridge challenge area.
- Shortcuts — missable bonus routes.
- Train / Monorail (Blue Tower) — scenic, slower, but completes the network.
How to Activate & Ride the Train
Good news first: activation is automatic. Clearing the Blue Tower switches the monorail on across the whole island — there's no separate switch, item, or quest step to "activate" it. From that point the three-coloured trains run on their own continuous loops, so the practical question isn't how to turn it on but how to use it.
- Board at any coloured station. Walk up to a red, yellow or green station and step into a car when one arrives; the trains circle the island past all seven stations, so you can hop on and off wherever you need.
- It's ride-along, not drive-yourself. The monorail is automated scenic transport — you ride it between regions rather than steer it. (Precise board / dismount controls are still being verified from a full playthrough, so treat it as hop-on transport for now.)
- Pair it with the other systems. For the fastest point-to-point trips use the Yellow Tower tunnels; the Green Tower cable car covers the east ridge. The train completes the network for relaxed, group-friendly travel.
Still being documented: the coloured station locations, the exact drive / board method, and whether the monorail and the three-coloured trains are one system. This page reflects the verified unlock (Blue Tower → Monorail) and flags the open conflict honestly rather than guessing.
Frequently Asked Questions
How do you start the train in The Big Walk?
You don't flip a switch — the monorail turns on automatically the moment you finish the Blue Tower, the fourth and final tower in the Red → Green → Yellow → Blue order. Clearing it switches the whole system on across the island.
Do I need to do anything to activate the train after the Blue Tower?
No. There is no separate switch, item, or quest step. The trains start looping on their own once the Blue Tower is complete, so the real task is learning how to board and ride them, not how to turn them on.
Which tower unlocks the monorail?
The Blue Tower — the last stop in the recommended Red → Green → Yellow → Blue order. It is the final of the four tower travel rewards, and the community generally saves it for last because the tunnels and chairlift already cover faster travel.
How do I ride the train once it is running?
Walk up to any red, yellow, or green station and step into a car when one arrives — the three-coloured trains circle the island past all seven stations, so you can hop on and off wherever you need. It is automated scenic transport, not drive-yourself.
Is the monorail or the train faster than the tunnels?
The tunnels from the Yellow Tower are the fastest point-to-point option. The monorail is slower and scenic, which is exactly why most players do Blue Tower last — by then it is a nice-to-have rather than a necessity.