Railroad bells sound not stopping

[Doomguy]

Making my map, I followed the train tutorial on his website and came upon a problem. The railroad bells sound will not stop even if I have an output in the timer telling it to stop after 5 seconds

Output to start sound: OnTimer/train_bells(name for ambient generic)/PlaySound (no delay)
Output to stop sound: Ontimer/train_bells/StopSound (5 second delay)

Does anyone know why this is happening?