CALGARY In the world of mechanical tower clocks, it’s considered good form if you can keep a clock running within three minutes per month. The clock at Calgary s historic city hall is currently running within less than one minute per month. That’s great news for Eric Brolund, the project manager for the rehabilitation of historic city hall. Brolund has become somewhat of an expert on the large timepiece. That’s because there are only a handful of experts in the world who know how to repair them and the specialist the city used is in his 70s and lives in New York.