A four-track-section from Sittard would complete a high-speed route into Maastricht, from Amsterdam and possibly from Nijmegen. The high-speed lines (HSL) from Utrecht to Eindhoven and its extension from Eindhoven to Sittard, and a HSL south to Liège, were described here earlier. This is an English-language version of the original post, with additional information for those not familiar with the Dutch network.
The existing line is double-track and electrified, but could not carry the extra traffic, and the alignment is unsuitable for high speeds. Additional traffic from a re-opened line to Aachen would also require reconstruction of the line out of Maastricht.
The existing railway was built in 1865, and its alignment is determined by the terrain. From Roermond to Sittard, the main line runs parallel to the river Maas. At Sittard, the South Limburg plateau begins, and the terrain slopes upwards. Another 10 km further south, the plateau is about 70 m above the floor of the Maas valley. The boundary between the plateau and the flood plain is a wooded escarpment.
The railway out of Sittard is aligned toward Maastricht, climbing slowly with the terrain. However, after Beek the plateau slope is too steep, and the line turns west to the Maas. For 8 km, between Elsloo and Bunde, the line is built on the escarpment itself. At Bunde it drops back to the Maas valley floor. After crossing the smaller river Geul, the line runs straight toward Maastricht station.
New plateau line
The line between Sittard and Beek is straight, and can easily be upgraded, with two extra tracks. Two new stations could be added in Geleen.
A new line can then do what was not possible in 1865: climb over the plateau. That is what the A2 motorway does, and it has the additional benefit of serving Maastricht Aachen Airport. The new line would be used exclusively by high-speed trains, that can climb steeper gradients. A tunnel would still be necessary at Bunde, where the line would drop 60 m, to rejoin the existing line. The junction would be just north of the river Geul, and from there the old line would be four-tracked.
This is not a true high-speed line (HSL), because it is only 20 km from Sittard to Maastricht via the plateau. It should however allow high speeds for through trains. The line passes the airport terminal, and obviously a station there is possible, but if all trains stop, there will be very little time gained. The future of the airport itself is in doubt, since like many smaller regional airports it is dependent on subsidy. (If there was no airport station, a long tunnel under the plateau would be an option).
Assuming that the new line serves the airport, then it would start north of Beek-Elsloo station, near the circular shopping centre Makado. It would first drop to pass under the A2 motorway, then climb again, staying as close to the motorway as possible to avoid a hill. With a cutting it should be possible to avoid a tunnel here, the climb is about 40 m.
Beek: base map by Jan-Willem van Aalst, CC4 licence…
Nearing motorway junction 50 there is another steeper slope, but the line would pass under the junction in a short tunnel anyway. The line could cross the motorway here: the airport is on the eastern side. The airport station could be on either side of the motorway, however, since the terminal is close by.
South of the airport, the motorway is split into two separate roads. Both are suitable alignments for a rail line, but the line must drop into tunnel here anyway. The airport is at 110 m elevation, the Geul valley floor below the plateau is at 45 m. On the images, the edge of the plateau is visible as an irregular forested strip.
At the Geul river, the new line would rejoin the old line. About 1500 m further is the junction with the line from Valkenburg (originally from Aachen). The existing layout into Maastricht consists of two parallel double-track lines, the Sittard line and the Valkenburg line. The new P+R station Maastricht-Noord only has platforms on the Valkenburg tracks.
What is needed is a four-track line into Maastricht, with separate fast and slow tracks. It must have at least one grade-separated junction, probably two – at the Geul river, and at the new station. A four-track layout will make it easier to add another new station at Limmel – a more logical site, between two residential areas. Finally, the sharp curve approaching the main Maastricht station, must also be improved, although the options options here are limited.
Northern Maastricht: base map by Jan-Willem van Aalst, CC4 licence…
The present Intercity takes 14 minutes for the Sittard – Maastricht journey. With a stop at the airport, even high-speed trains will not take less then 10 minutes for the 20-km journey. However, the new line is also intend to increase capacity. On the existing line, the four new stations would be served by a regional metro. Stations are also possible at Elsloo village, and at Geulle (the old station there closed in 1945).
The airport station determines the alignment of a surface line over the plateau. Without an airport station, the new line does not need to be on the plateau anyway: it can use a ‘base tunnel’ from Beek to Bunde. The long tunnel would also start just north of Beek-Elsloo station, with a junction at the Makado shopping centre, at about 75 m elevation. It would pass under the road to Elsloo village (Stationsweg), and dive into the hillside behind the road.
The tunnel would emerge in the sports fields at Bunde, at about 65 m elevation. The line would then follow the A2 motorway, on viaduct, to the existing line. To avoid a sharp curve here, the junction would be about 2 km further on, about 1000 m from Maastricht-Noord station.
The new line would be about 10 km long, of which 7 km in bored tunnel under plateau. With no airport station, and an almost straight and level tunnel, journey time Sittard – Maastricht should be about 8 minutes (average speed 154 km/h).