This is NOT a roadside cache and parking on the busy main road should NOT be attempted.
As you walk towards the cache from 'Sleeper on the Bench' you can see the trackbed splits in two before reaching Newtyle Road and the two lines used to cross the road over separate bridges (now gone). The higher (southern) of the two is Ardler Junction overbridge heading to Perth, the lower northern one is the Alyth Junction overbridge.