Michael Birch, 44, was one of 23 people injured in the East Mersea accident near Colchester, in September.
He had to be cut free from his cabin by firefighters and was airlifted to hospital having sustained deep lacerations in his abdomen.
After seven operations, Mr Birch has returned home to continue his recovery.
The father of four has no memory of the four days after the crash when he underwent stomach surgery , two shoulder operations, skin grafts and the reconstruction of a hand.
Recalling the moment of impact on 23 September, he said: "I was driving along and just bang, just felt this shunt sensation.
"I woke up and the bus is a wreck around me, passengers are screaming and I'm sitting in the seat and holding onto my stomach contents, which had just burst out.
"A low-loader had come past, but the traction engine that was on the back had fallen off and smashed into the bus - literally just made a massive, massive mess."
He described feeling helpless as he was unable to move to help any passengers.
He said: "I was worried that with the stomach, the way it was, I just thought I was going to die. People were screaming. It was horrible."
By his hospital bedside was his wife Gemma, who was shocked to see him so ill.
She said: "When the police turned up telling me that he was alive. We just had to go, it was scary.
"He had tubes and wires, monitors kept bleeping, just telling me he was really poorly."
Mr Birch said they had received great support from their friends and family, and had one message for those who have helped.
He said: "To everybody that supported me and who has asked about me and has helped raise money to help us and stuff, I just want to say thank you. It just restores your faith in humanity."
A 51-year-old Great Yarmouth man arrested on suspicion of causing serious injury by dangerous driving has been released on police bail until 3 January.
For the full interview, listen back to BBC Essex's breakfast show from 06:00.
A bus driver who was seriously injured in an accident when a traction engine fell off a low-loader into his cabin has told how he thought he "would die".