The proposed urban-regional metro Aachen (S-Bahn) would increase traffic on the rail line into Aachen, from the north. A city-centre tunnel is essential: the existing line into Aachen Hauptbahnhof curves around the historic city centre. It could not be widened without substantial demolition – and there is no point in that, because the alignment itself is so bad.
Click to enlarge: the proposed central Aachen tunnel, with Vaals branch…
However, even with a new central tunnel, there would still be capacity problems on the Aachen – Mönchengladbach line through Laurensberg and Richterich. The line has several curves – partly because of the topography, but also because it was re-routed in 1910. Just north of the former Richterich station, there was a junction with the former Maastricht – Aachen line. The junction, the curves, and the line on viaduct through Laurensberg, make 4-tracking difficult.
Here, new tunnels are considered, to increase capacity on the line. One has been proposed already: a tunnel under the ridge at Laurensberg, for the proposed high-speed line Sittard – Aachen.
Click to enlarge…
This tunnel is not compatible with use by other services. However, a second tunnel on a similar alignment could carry two proposed regional metro lines:
- the re-opened line Maastricht – Valkenburg – Aachen, using the disused section through Bocholtz and Vetschau.
- the new direct Aachen – Heerlen line, most of it in tunnel.
The second Laurensberg tunnel would not be used by the proposed second Aachen – Heerlen line via Kerkrade. That line would use a new link from Kohlscheid around Kerkrade, or possibly under central Kerkrade.
Click to enlarge: the future lines through Richterich and Laurensberg, regional metro in orange…
Both the HSL tunnel and the regional metro tunnel, would start at the north end of the former goods yard Aachen-West. The topography is the same for both. First there is a shallow valley, used by the ring road (Pariser Strasse), then a slight ridge with the IKA vehicle test track. This test facility is the northern tip of the RWTH (Technical University) campus.
The line would cross a second deeper valley (Wildbach), with some historic farms and mills. The new line would cross it on viaduct, and then dive into the slope on the other side. (The existing line bends 60° here, to avoid this slope). The new line would climb in tunnel, to the plateau above, emerging between Bocholtz and Vetschau.
The alignment as a whole is approximately level. However, it could dip or climb locally, to minimize environmental impact on the surface. The most sensitive area is the Wildbach valley, but the existing line effectively minimizes impact, by crossing it on a high viaduct.
The HSL tunnel would join the alignment of the motorway (A4 in Germany, A76 in the Netherlands). It has no stations, so it would take the shortest route. The regional metro tunnel could bend more to the east, allowing a new Laurensberg station, where the tunnel crosses the Orsbacher Strasse. However, the station would be in relatively deep tunnel (20-30 m), and at the edge of Laurensberg anyway. The disadvantages outweigh its benefits.
The two tunnels would therefore have similar alignments, possibly next to each other. All variants are about 2500-3500 m long, from the freight yard to the northern tunnel portal. Close to Vetschau, possibly between Vetschau and the A4, the regional metro line would split. One line would run along the east side of the A4, toward Avantis and Heerlen, the other would join the old Maastricht alignment, outside Bocholtz.
Click to enlarge: regional metro tunnel at Laurensberg, with two possible variants shown…
This solution would segregate traffic on the regional metro lines from Heerlen and Maastricht, from traffic from Herzogenrath. An alternative option is to use the existing line through Richterich for the regional metro, and re-route other traffic from Herzogenrath and Mönchengladbach.
This ‘ Richterich bypass tunnel’ would start at the northern edge of Richterich, where the rail line crosses the Amstelbach. It would drop into a cutting, pass under the Horbacher Strasse, and then enter a tunnel. The tunnel would emerge, like the others, on the side of the Wildbach valley, which the line would cross on viaduct. Like the other options, it would join the existing line, at the former freight yard.
The variant shown is curved extra to the west, to minimize impact on housing in Laurensberg. The tunnel might also dip downward, for the same reason. (The terrain rises about 25 m, from the Amstelbach to the schools at Laurensberg). The option shown passes the former Karl Friedrich Mine, but the old mine workings are far deeper.
Click to enlarge: Richterich bypass tunnel…
The Richterich bypass alignment would be about 3800 – 4000 m long, almost all in tunnel. Together with a 4-track section through Kohlscheid, this option would keep all trains from Herzogenrath clear of the regional metro lines. They would however, all pass Aachen-West, which would be used as an interchange station.