The Gateway (GTW) is complaining about a state mismatch between the drive rail requested and the current one sensed. There are three scenarios that can cause this alert to appear:

1. The Drive Rail was requested "On" by the Gateway, but it is stuck in the "Off" state. This is possibly due to a relay that will not unlatch. 
2. The Drive Rail was requested "On" when it is already in the "On" state. This is most likely a bad sense lead in the Gateway.
3. The Drive Rail was requested "Off" and it is stuck in the "On" state. This is possibly due to a relay that will not unlatch?.