Nauen is on the main line Berlin – Hamburg, that is partially upgraded as a high-speed line (HSL). A new rail link into Nauen, from the Berlin – Hannover HSL, would allow rationalisation of services. In combination with new infrastructure between Nauen and Potsdam, and a new regional rail service Nauen – Oranienburg, it would create a new regional rail junction. The region is thinly populated, and Nauen itself is a small town (population 16 000), but there is no other suitable location.
The Hannover – Berlin high-speed line was built on a pre-existing alignment (Lehrter Bahn), which is still in use for other trains. The result is, in effect, two parallel railway lines, one partly electrified. Stendal has a separate bypass for high-speed trains, on the right in the image below.
HSL bypass of Stendal starting at Möringen: image by Sebastian Terfloth under CC-SA-3.0 licence…
However, east of Rathenow, there is a 17-km section without parallel track. This low-lying area (Havelländisches Luch) is the main German habitat of the Great Bustard, the largest flying bird in Europe. The species is so endangered that a tunnel was considered, and the line was designed to prevent train-bird collisions. On this section there are two stations, serving small villages, Nennhausen and Buschow. Both have through tracks for high-speed trains, but it is still unusual for a high-speed line.
This solution works at present, because train frequency is low. The hourly Regional Express line RE4 runs Rathenow – Berlin – Ludwigsfelde – Jüterbog, sometimes starting at Stendal. Despite the name, it stops at all stations to Spandau. West of Rathenow, RegionalBahn line RB13 runs to Braunschweig, via Stendal, Oebisfelde and Wolfsburg (every two hours, hourly from Stendal on weekdays). Since not all track is electrified, it uses Desiro diesel units. Stendal is also served by some Intercity trains, but only one at regular intervals: the two-hourly Berlin – Amsterdam service.
With the opening of the proposed Wustermark – Nauen link, regional services from Spandau via Staaken, Dallgow-Döberitz, Elstal and Wustermark could terminate at Nauen, 35 km from central Berlin. Regional and inter-regional trains for stations further east could also use this link, if they can turn back to the Hannover line. That is the logic of the link line proposed here, west of Nauen. The diversion via Nauen would add about 5 km to the route, but improve interchange.
The new link does not dictate a service pattern. The present services (Regional-Express to Rathenow, RegionalBahn from there to Braunschweig), could be retained. However, it is logical to combine the new link with full electrification of the parallel tracks, and an additional track through the Havelländisches Luch.
That would allow three levels of service: a non-stop ICE Hannover – Berlin on its existing route, an inter-regional service via Wolfsburg, Stendal and Nauen, replacing some present Intercity services, and regional services for the remaining stations. With a new grade-separated junction on the Berlin side, Rathenow could also be served by the inter-regional trains. Regional services could run west from there, as at present, or they could be split into Hannover – Stendal and Berlin – Stendal lines. (Stendal is the junction with the north-south line Wittenberge – Magdeburg).
Another option is to close the stations at Nennhausen and Buschow. The area served is Amt Nennhausen, with only 4750 inhabitants, and a density of under 20 persons/km². With closure of the last intermediate stations, Rathenow would be served by inter-regional trains running non-stop from Nauen.
The new western link to Nauen would start at Gross Behnitz, east of the Havelländisches Luch. It would pass between Lietzow and Nauen, and join the Hamburg line just west of Nauen station. The line crosses forest and farmland, and there are no obstacles to construction.
The new link would be 10 km long. It would have no intermediate stations, and the new route does not displace any other station. (Neugarten and Gross Behnitz stations are closed).
East of Nauen, some trains could use the Hamburg line to Spandau: the proposed upgrading of the line includes four tracks from Nauen. For all these services on the Hamburg and Hannover lines, Nauen would be an interchange station, with additional services to Potsdam and Oranienburg. An additional option is a new link line to Brandenburg, diverging from the Nauen – Wustermark link.