Like if ACT came with a rail designed by Burley Griffin? (10,4)

'rail designed by burley griffin?' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe there's a link between them I don't understand?

'like if act came with a' is the wordplay.
I cannot quite see how this works, but
'if' is found in the answer.
'act' could be 'art' (art is a kind of act) and 'art' is found in the answer.
'a' is within the answer.
This explanation may well be incorrect...

Can you help me to learn more?