Michael and Trevor set off on a train heist hoping to get enough gold to pay off their wrongdoing against the ever-powerful Martin Madrazo. While Trevor only wants it for the money and the thrill of hitting a train, Michael needs to pull this one off to go back to his life in Los Santos.
In this guide, we will be showing you how to finish the Derailed mission in GTA 5 and get its Gold Medal completion.
Derailed Mission Guide (Gold Medal) – GTA 5

Michael, who is currently forced to live with Trevor in his trailer, grieves about his life in Los Santos.
Soon enough, Ron arrives at the trailer and has a quick chat with Michael. After a bit of back and forth where Ron gets a warning from Michael, he reveals that Trevor’s monthly train is on the way.

Curious about what the monthly train was, Michael tries to ask Ron for further information. However, before he could do just that, Trevor arrives with Patricia.
Trevor reveals that it is a train heist job he was planning and it could have enough gold to pay off their sins against Madrazo, taking Michael back home to his family.

The two then sets off to Raton Canyon Bridge to chase after the train, thus, starting the mission.
Derailed Mission Guide

The mission starts with Trevor. Get on the motorbike and head to the waypoint on the map. The game should tell you to jump onto the train.
Go as fast as you can as the time spend chasing the train affects your goal of getting the Gold Medal.

Just follow the blue marker on your map until you reach the target train. When on the tracks, shift to the right side of the train.
Follow the train closely until you reach this ramp. Be careful not to hit the train as it might crush you on the tracks or derail your momentum, hindering your quest for the Gold Medal.

Hit the ramp as fast as you can to jump onto the train.

Now that you are above the train itself, drive along it to the engine at the front. Be careful not to fall.
A short cutscene should trigger where Trevor knocks down the train conductor.

Maneuver the train until the game automatically switches you to Michael.
Now controlling Michael, drive the speedboat to the bottom of the bridge where the two trains should collide.

A small cutscene should trigger again. Trevor jumps from one of the trains to the water below.

Get in close to the orange container using Michael and throw a sticky bomb at its doors. Blow it up to open the container.
ALSO READ: GTA 5: Three’s Company Mission Guide (Gold Medal)

The perspective should then switch back to Trevor. Shoot the incoming Merryweather goons while Michael gets the goods inside the container.

After taking down the enemies on the water, use the Sniper Rifle with thermal scope to shoot down the snipers on the bridge.

After that, enemies should then come from above. Some will be parachuting down while helicopters come to take you down. Shoot every one of them down.
With all Merryweather goons taken down, dive into the water to the dinghy with Michael.

Ride down the river while shooting the chasing mercenaries.
Go to the beach where your getaway vehicles are.
The ending mission cutscene should trigger.
Derailed Mission Gold Medal Requirements
Mission Time: complete the mission within or under 11:30. Skip all cutscenes if necessary.
Fastest Speed: reach top speed in the Sanchez motorbike using Trevor. Push down the accelerate button for as long as you can while avoiding incoming traffic.
Better than CJ: land on top of the train within the first jump. If you miss the jump, better retry the whole mission altogether.

There you have it! Follow the steps we provided above and you should have that Gold Medal in no time!