Tim Dunn sees how quirky railway architecture has shaped the city of Lincoln.?The rivalry of two competing Victorian railway companies and their refusal to share infrastructure not only resulted in two railway stations, but two level-crossings that cut the busiest thoroughfare in the city in two.In Birmingham, Tim takes an exclusive look at a brutalist signal box, just before it switches off the lights, for the very last time. And, at the Network Rail archives Tim gets his hands on Stephenson's drawings for two great Victorian bridges - the Newcastle High Level Bridge and the Britannia Bridge.