Citytunnel’s first TBM has reached Malmö Central Station

The TBM Anna broke through the excavation wall at Malmö C on Tuesday afternoon. This means that she has reached her final destination on a 4.6 km long journey. “The boring has been very successful, no major surprises or setbacks and we are on time” says Johan Brantmark, assistant project manager at subproject Tunnels.

Anna started to bore in Holma in the end of November 2006. She has taken almost 500 days to cover 4.6 kilometres. The machine has done several planned stops along the way – one three month maintenance stop in the rock cavity at Triangeln, two Christmas stops and several short maintenance stops. The last leg, between Triangeln and Malmö C, was the most complicated distance to bore, with one sharp turn and with higher water content and more cracks in the limestone rock. ”It was definitely more water. It made the maintenance stops a little more complicated, but we have managed the distance without any greater difficulties” says Johan Brantmark. The 1.9 kilometres between Triangeln and Malmö C took 130 days, which is an average speed of 15 metres per 24 hours. ”There are substantial differences from one day to another. Some days the machine has been standing still for maintenance and other days the progress has been very good. The record is 36 metres in 24 hours” says Johan Brantmark. ”Now that we can summarize the boring of the first machine, it has been very successful, no major surprises or setbacks. And above all, we are on time” says Johan Brantmark. Anna’s sister machine, Katrin, is standing still for maintenance, about 500 metres from the excavation wall in Malmö C. Her breakthrough is estimated to take place in one month.