Basel's tram expansion plans should go further

Basel has a good tram network comprised of 13 lines across 79 route kilometres. Trams generally run every 7 minutes and somewhat uniquely, the system extends into three countries, reflecting Basel's position spanning Switzerland, France, and Germany.

Here's what that network looks like today. Note: I've only shown the city core for sizing purposes.

All lines flow into the densely-packed city centre, where multiple lines share the track as they pass through. This ensures that tram riders can access the city centre without a transfer but it also means that the downtown tram tracks are very crowded. With the central track segment at capacity, trams have to slow down and there isn't room to increase service levels on one line without reducing service on others. Moreover, the central segment is a single point of failure - when disruptions affect it, almost all tram service in the city has to be rerouted.

The Kanton of Basel-Stadt is planning to build a series of new track-segments to free up capacity and improve reliability in the city centre. Collectively, these projects, shown below, have been dubbed Tramnetz 2030.

When complete, the network will look like this. The notable change is that five lines will share the central segment, instead of six.

This is a great plan, and does a lot to improve operational reliability with relatively little infrastructure.

I think it could go a lot further though, to really fill in some missing connections and expand the reach of the network. So, just for fun, I thought I'd sketch out what I think Basel's next wave of tram expansion should like, perhaps for Tramnetz 2040.

The Kanton of Basel-Stadt actually has a "next step" already in the works: a new tram line into the Bachgraben area, which is the site of numerous pharmaceutical offices and has grown substantially in the last 10 years. It's not official yet, but I expect this new line would become part of Line 21, as shown below.

I'm not sure this is a great idea. Most people commuting to and from the Bachgraben area come from around the region, not just the industrial north end of Basel where this new line would connect. I fear this proposed line is the easy choice - the cheapest and simplest way to build a tram that technically serves the area - rather than the right choice.

If it were up to me, I would scrap this proposal and would instead tunnel a branch of Line 6 beneath the Bachgraben and out into the French village of Hégenheim, which is also a big commuter town. This would provide a more direct connection between Bachgraben and the city centre, allow people to travel more directly to it from other lines.

I would further extend Line 11 into the french towns of Saint Louis and Huningue, which are the biggest population centres in the city not currently on the tram network. A new route through the Roche Campus also makes sense. This one of the biggest employment clusters in the city, as I mentioned in a previous post, but still isn't directly served by the tram network.

I recognise that "map-based planning" like this often leads to frivolous decision making, but I think these three projects are justified. They would each fill in key gaps in the existing public transport network and thereby help make public transport more attractive and useful to more people. That, to my mind, should always be the goal.