Dr Emmett Brown's first trainspotting trip, last December, took him back to 1950, to see the railway at Freshwater, Isle of Wight:     This weekend, he has had a major trainspotting journey, starting by going back to the 1920's to watch the Great Western in action at Modbury.     Then he traveled forward to the 1950's to check out the brewery at Wickwar.     Then he went forward a bit more to the late 1960's and visited City Basin Goods