Virus

The virus is an unknown entity found in train world. It can infect a train by entering it. Once infected, a train will move in all directions spontaneously, draining their energy until they eventually derail. According to Selly, It is the same virus that infected Duke. On a robot train, it drastically modifies their engine and personality, as seen with Duke, who attacked and tried to take Kay's engine. According to Vito, he said he felt clanky after contact with the virus, though he probably did that to be with Selly. When Selly came, she said he did have a clanky engine and, to Vito's surprise, took him apart to fix him.

Appearance
On the outside of a train, it looks like a mysterious colored light with a smoke trail. In an engine, The virus looks like a black pixelated mold.

Behavior
The virus has a tendency to follow energy on the rails, helping it to eventually meet an unlucky train also on the rails. The virus avoids water. It is unknown what happens when it touches water."'You can't come near the water!' - Duck"The virus stops in midair when it encounters a dead end rail. This led to the virus's ultimate downfall as it gave Kay a chance to overload the virus.

In an engine, the virus creeps around walls and tunnels. It swallows and deletes any memory it touches inside. Touching a train inside will warp the train back into reality. When the robot trains confronted the virus within Duke's engine, it turned a small chunk of itself into a "zombified" Duke. At the center of the engine, it managed to turn itself into a whole giant Duke. It likely takes a zombified form of whoever it infected.

Cure
Selly possesses an antivirus in the form of a nano-bomb. It can be administered to any train with the virus by placing it on them while they are held down. It is shown to destroy the physical form as Duck threw one at the virus, even though he slipped and dropped the bomb on the ground nearby. Upon getting placed down, the antivirus explodes and releases a gas.