Askerbanen

Two tracks had become one bottleneck

By the time the project took shape, Drammenbanen's capacity through the western corridor was fully used. Local trains with frequent stops shared the same pair of tracks as regional, airport, long-distance and freight services. A faster train could not simply pass a stopping train; the timetable had to make every movement fit the same railway. 01 05

The need for intervention appears in public planning as early as 1985-86 and again in Oslo Package 2 in 1997. The stated aims were broader than speed: more capacity, better punctuality, shorter journey times and a larger share of travel by public transport. 04 05

Eighteen years from idea to complete line

NSB presented the project in 1993 as a new double track from Skøyen to Asker. The first impact assessment considered a wide range of possible routes. A second assessment in 1996 recommended a surface station at Lysaker and a railway in tunnel westwards towards Engervannet — recognisably the solution eventually built. 05

Municipal plans through Bærum and Asker were adopted in 1998. The project did not then move straight into construction. Route choices, the order of the stages, the future of Fornebu and the detailed design were still being argued and tested. Vista Analyse counts roughly eighteen years from the planning start to completion of Lysaker-Sandvika. 05

The new railway would go via Lysaker

Fornebu made the route decision more complicated. Oslo asked for alternatives that took the main railway by the redeveloping former airport. A 2001 supplementary study compared those options with the route through Lysaker. 05

The government chose the H alternative: the new double track would serve Lysaker rather than loop through Fornebu. The assessment judged it better suited to the railway's transport task, less expensive, easier to build in stages and faster for regional passengers. A separate public-transport connection was intended to link Fornebu with Lysaker. 05

It was built from the outside in

The 1996 planning work originally placed other sections ahead of Sandvika-Asker. A later national analysis reversed that order after finding the strongest early socio-economic benefits in the outer sections. Sandvika-Asker therefore became the first construction stage, built from 2001 and opened in 2005. 02 03 05

This gave the corridor a new pair of tracks only west of Sandvika. It was strategically useful, but incomplete: trains still had to share the old bottleneck farther east. The later evaluation is important here because it does not pretend that laying the first rails immediately delivered the whole promised result. 05

A railway mostly hidden from view

The fast pair spends much of its journey in rock. Its four principal named tunnels are Bærumstunnelen, 5,790 metres; Tanumtunnelen, 2,790 metres; Skaugumtunnelen, 3,790 metres; and Askertunnelen, 416 metres at the Asker station area. 05

Around Sandvika, four concrete tunnels carry their own names and lengths: K73 at 243 metres, K72 at 197 metres, K74 at 108 metres and K91 at 397 metres.

The tunnel alignment kept most of the new railway away from dense residential areas. The 2021 evaluation found that this reduced conflict with vulnerable nature and cultural environments and improved long-term noise exposure compared with a surface solution. 05

Lysaker had to become part of the new railway

The station was more than a platform project. It grew from two to four platform tracks, gained a broad passage beneath the railway and was connected more closely with buses and taxis. The project also included 0.9 kilometres of new double track and a new railway bridge over Lysakerelva. 04 05

Construction work began in the mid-2000s, and the rebuilt station officially opened on 1 September 2009. That removed one bottleneck and prepared the eastern end for the final connection to Sandvika. 02 05

The last gap went under Bærum

The first of four major Lysaker-Sandvika contracts began in March 2007. The new alignment runs beneath the villa districts from Lysaker towards Engervannet, then reaches daylight and approaches Sandvika alongside the older railway. The project built 5.6 kilometres of new double track in this final section, including the 5,790-metre Bærumstunnelen. 05

The complete facility entered service on 26 August 2011 and received its official opening on 2 September. With that, four tracks extended continuously from Lysaker to Asker. 04 05

Four tracks work because the trains are separated

Askerbanen was built to a standard allowing 160 km/h. The older Drammenbanen remains a railway of local stations and lower speeds. In practice, the new pair carries freight, airport, long-distance and regional traffic while the older pair carries the local trains. 01 05

The project target was capacity for 26 trains in each direction per hour after the complete programme. A local stop at Høvik or Blommenholm no longer has to occupy the same path as a through train beneath Bærum. 05

New tracks were necessary, but not sufficient

The 2012 evaluation of the first Sandvika-Asker stage was restrained. Only marginal timetable improvements had been made, so the expected socio-economic benefit had not yet appeared — even though the investment was still judged strategically right. New rails create possibilities; they do not write a better timetable by themselves. 05

Later service changes, new rolling stock, more stabling capacity, power-supply work and renewal of the older Drammenbanen allowed more of the corridor's capacity to be used. In 2021, Vista Analyse's evaluation of Lysaker station and Lysaker-Sandvika found high goal achievement and socio-economic value substantially better than forecast. The Railway Directorate's summary says the works helped shift the competitive balance between car and train more than expected. 04 05

Askerbanen's value emerged as train services and the surrounding railway were adapted to use the new capacity.