Graeme Harper - best-known for his long career on Doctor Who - was recruited by the soap's producer Phil Collinson to take charge of the spectacular scenes, which air in a double bill on Monday.
As announced earlier in the year, a huge explosion at The Joinery bar will cause a tram to fall from the viaduct above, resulting in devastation and deaths on the cobbles.
Speaking to Inside Soap, Harper commented: "I hope I'll have succeeded in surprising the audience when the crash actually happens. They'll be expecting it - they know it's going to happen - but they don't know exactly when. I hope I give people that shock.
"When I watched it back, my mouth was hanging open for the rest of the episode - and I made it! At the end of it, I was crying - I was in tears from the shock of what I'd just seen. I think it's absolutely fabulous, and I hope people like it as much as I do."
Coronation Street's tram crash will be one of the highlights of the show's 50th anniversary celebrations.
> In Pictures: Corrie's anniversary disaster
> Full Coverage: Corrie's 50th anniversary