Big Hill#The Spiral Tunnels
The spiral tunnels are two spiral tunnels on the trans-continental railway line of the Canadian Pacific Railway (CPR ) in the Canadian province of British Columbia. They are located west of the Kicking Horse Pass, which forms the watershed in the Rocky Mountains. When the tunnel opened in 1909, they were considered technical feat.
1884 reached the construction crews of the CPR the Kicking Horse Pass. In the first six kilometers west of the 1627 meter high pass the terrain falls towards Field by no less than 350 meters. There was no way to extend the route through the Kicking Horse Canyon or the Yoho Valley artificially in order to reduce the gap. To save time and money, the tracks were laid in a straight line as possible; characterized the track had an average slope of 4.5%. This was four times higher than the recommended time for Railroads steepest descent. Even today, railways often steeper than 2%.
The railway workers called this risky section " Big Hill ". For the uphill road towards the East, in Field special steam locomotives, so-called " Pusher " ready to increase the tension. The working conditions were very hard. In winter there was often blizzards and temperatures dropped often below -30 ° C or even -40 ° C. All the time there was a danger of avalanches or landslides. Often, steam locomotives were resting because of congestion or dissolved cars of the trains, which then sped downhill and derailed.
Early 20th century it had become inevitable due to the ever- increasing traffic that something had to be done to alleviate this bottleneck. The engineers were faced because of the steep rock walls with lack of space. The problem was solved by two spiral tunnels were drilled on the Swiss model in the two mountain sides. This allowed the track to be artificially lengthened and reduced the gap to a manageable level.
The first leading westward route reaches the upper tunnel or tunnel No. 1 ( 51 ° 25 ' 17 "N, 116 ° 25' 8" W51.421476590556 - 116.41890048972 ), as he is called the railwaymen. This is 992 meters long, turns at Cathedral Mountain to 288 ° and ends 15 feet below. The route now leads to the northeast over the Kicking Horse River and reaches the lower tunnel or tunnel No. 2 ( 51 ° 26 '10 " N, 116 ° 24' 13" W51.436019115556 - 116.40353679667 ). In this 891 -meter-long tunnel, the route turns in Mount Ogden to 226 ° and then runs again 15 meters deep westbound. The route takes a total of three times (on different levels ) through the valley and crosses the river four times.
The tunnel had to be drilled into highly sophisticated, crystallized limestone. The hardness and brittleness of the rock changed every few meters, which greatly complicated the construction work. In addition there were water leaks, altitude (around 1500 m above sea level ) and harsh winter weather. Thus the already harsh working conditions have been further reinforced.
The construction of the helical tunnel the maximum slope of the section of 4.5 % was reduced to 2.2%. The spirals extended the distance of 12.5 kilometers. Thanks to these improvements had only two instead of the previous four locomotives are used. These were beyond even longer trains, which considerably lowered the operating costs.