Can't see any other example maps on this.
Basically a tracktrain travels to a stop point where an env_physconvert, env_explosion and env_physexplosion are triggered.
Env_explosion is used to simulate the cannon fire from the left, whilst the physexplosion effects the tracktrain that has been converted to a physics object.
Additional sprites etc can be added to convey a more realisic effect.
Enjoy, if you need help using this then pm me.
I didn't know you could do that either.
It will be come handy - at least it will for me