The northern ramp to the entrance of the tunnel is 600 m long and has a slope of 40 ‰[1] It was planned that each hour and in each direction, there would be up to ten S-Bahn, two regional trains and one express (as of July 2007[update]).

The implementation was planned as an underground railway, running parallel to the two mainline tracks from Borsdorf via the Hauptbahnhof and the Bayerischer Bahnhof and on to Connewitz and Gaschwitz.

[citation needed] During World War II the tunnel and underground stop were converted to provide air-raid shelters.

During the bombing raid on Leipzig on 7 July 1944, there were two explosions that destroyed the tunnel at two places and thus divided it into three parts.

During reconstruction of the main station, the area around the second impact point was walled-in, and the platform under the east portico converted into the DEFA-Zeitkino Cinema and was used for this purpose until 1992.

[citation needed] Shortly after World War II, in 1946, planning for an underground city crossing restarted.

In order to accommodate the entrance of the tunnel, redevelopment work at the corner of Windmühlen- and Grünewaldstraße was delayed.

Due to the expected high financial and technical effort, the plans were not realized before the end of the GDR.

It is hoped that shorter intervals and faster connections will allow public transport to carry more passengers and thereby relieve road traffic in the city.

In addition, it will bring more passengers directly by rail from Leipzig Hauptbahnhof to the city centre and convert the terminus to a partial through-station.

[citation needed] Additionally, it was planned to run one intercity train per hour in each direction through the tunnel.

Therefore, the states of Saxony and Bavaria, the Federal Government and DB were planning to continue rail electrification first to Hof, and later on to Regensburg and Nuremberg.

[citation needed] Early in 2002, the Saxony State Government gave support for the implementation of the City Tunnel.

[11] After the estimated total costs had risen by the end of November 2009 to 893 million euro, the state auditors of Saxony reviewed the project.

[7] The federal share provided is limited, in line with the framework agreement, to 191.73 million euro (plus wage and price increases).

The additional costs are mainly supported by the Free State of Saxony and the City of Leipzig, and to a lesser extent, the German Railways.

When constructing Leipzig Hauptbahnhof, the Saxon State Railway had planned a tunnel to Bayerischer Bahnhof.

In 1913 and 1915, a 710m long section below tracks 22 and 23 was created before the work came to a halt due to World War I and a lack of funds.

[citation needed] At the start of the construction process, the tunnel was planned to be in operation by late 2009.

The tunnel's godmother is Angelika Meeth-Milbradt, wife of then Prime Minister of Saxony Georg Milbradt[18] The excavation began on 15 January 2007 and on 10 March 2008 reached the railway station, so completing the first bore.

Ahead of the expected opening in December 2013, activities centred on the interior fitting-out of the tunnel and railway stations.

This mass then formed a waterproof wall through which the tunnel boring machines could run without the surrounding water and rock penetrating.

Using this approach, however, there is a danger that the pressure is lost due to old water wells with the collapse of the ground in front of the tunnel boring machine.

The shortest distance between the building foundation and tunnel roof is under the Petersbogen underground carpark at 2.20 metres.

The plans include two tunnel excavations with a diameter of 2.40 m using compressed air and a cover plate.

Partially, the soil was already previously raised by a few millimetres in order to reduce the final setting depth.

For the case that the uplift not the actually occurring reduction can compensate, further cement is pressed into the ground and kept the buildings at a constant level.