Karlsruhe, in Germany's Baden-Württemberg region, has blurred the distinction between its trams and railways.
In Karlsruhe, the tram system is connected into the local rail network, pioneering the tram-train concept which has since been adopted by several other cities.
Karlsruhe's main railway station, Karslruhe Hauptbahnhof, lies around a kilometre and a half south of the city centre. Prior to the introduction of tram-trains, passengers travelling into Karlsruhe on local trains would have changed there onto the city's tram system to reach the heart of the city.
A key benefit of the tram-train concept is that it enables passengers from the surrounding region to travel directly into Karlsruhe city centre without having to interchange from train to local transport at Karlsruhe Hauptbahnhof. The time savings and greater convenience offered have resulted in some impressive growth in ridership.
The tram-trains are dual-voltage, using drawing AC power from the overhead system on the rail network and DC power when running on-street.
Line S4 is particularly interesting. It operates on-street in Karlsruhe, then on heavy rail infrastructure to the town of Heilbronn around 60 kilometres to the east where it returns to on-street running through the town centre.
Heilbronn is the easternmost extremity of the tram-train system; to the south west, the tram-trains reach as far as the spa town of Baden-Baden.
The success of the tram-train concept has been so great that, to tackle increasing congestion on the tram system in the centre of Karlsruhe, a tunnel is being built beneath the streets. Once completed, tram-trains will be rerouted through it enabling Karlsruhe's main shopping street to be completely pedestrianised.
Not all the tram-train routes operate on street. These images (left and below) were taken at the city's main station, Karlsruhe Hauptbahnhof.
Lines serving these platforms operate entirely on railway infrastructure, and do not reach the heart of Karlsruhe.
Close to Karlsruhe Hauptbahnhof is the Albtalbahnhof tram-train station. This is used by several tram-train services leaving the railway network to continue their journeys on-street and vice versa. Tram-trains serving Abtalbahnhof also stop in the forecourt of Karlsruhe Hauptbahnhof.
The tram-trains which run on-street share Karlsruhe's system with conventional trams. Both are seen in this image.
Karlsruhe's city tram system comprises mainly modern, low-floor cars.
Buses complement the tram and tram-train network. As in a number of other cities I have visited, the buses operate primarily in the suburbs where they act as feeders to the rail-based services. A small number of bus routes reaches Karlsruhe Hauptbahnhof, but do not penetrate the city centre.
The buses are operated by several companies. Although they are co-ordinated by Karlsruhe Verkehrsverbund (KVV), the public transport associaiton for the Karlsruhe area, they wear the liveries of their individual operators.
Two further bus routes connect with the tram-train network at Abtalbahnhof.
Just one bus route reaches the centre of Karlsruhe. Route 73 approaches the city from the north.
As well as standard single-deckers, articulated buses also operate in Karlsruhe.
Fares on Karlsruhe's public transport system are based on a zonal tariff system. At the time of writing (June 2014), a single fare within Karlsruhe costs €2.30, valid for 90 minutes with interchanges permitted. An all-day ticket costs €6 for one person, or €9.50 for up to 5 people travelling together. For travel beyond Karlsruhe itself, higher fares apply. The validity of a single ticket also increases, up to 4 hours for tickets covering 6 or more zones.
The Karlsruhe Verkehrsverbund (KVV) website provides fare and timetable information for public transport services in and around Karlsruhe. More about the tram-train concept can be found on numerous other websites, including the Karlsruhe Model site.
Despite the tram-trains, Karlsruhe does have one rail system which is entirely self-contained.
A miniature railway operates in Karlsruhe's Schloßgarten (castle gardens) at weekends during April and May, daily from June to the end of September. Both steam and diesel locomotives are used. The railway was opened in 1967, the year in which Karlsruhe hosted Germany's federal horticulture show.
Since this is a leisure attraction rather than a public transport service, special fares apply. A further supplement is charged to travel on the steam-hauled train. Nevertheless, the Schloßgartenbahn does appear on KVV's publicity, including its website (although the information is available only in German).