Being a state capital has some advantages, and despite its small size, Saarbrucken gets its own high-speed ICE line, making it easy to reach from anywhere in Germany. In about two hours the line takes you as far as Frankfurt, from where you can go just about anywhere. Regionally there are direct lines to towns like Kaiserslautern, Trier and Koblenz. Internationally there are also direct lines to Paris, Strasbourg and Luxembourg.
Numerous bicycle routes are signposted all over the Saarland, thanks in part to the persistent lobbying efforts of the General German Bicycle Club (ADFC).
Here there is even a sign (near the theater in Saarbruecken) pointing to the ADFC regional office.
(I am of course a member of the ADFC, but in Frankfurt not Saarbruecken.)
Currently there are nineteen direct trains from Frankfurt am Main to Saarbruecken on an average day. Four of these are InterCityExpress trains (ICEs), but that doesn't make them particularly fast because the tracks don't allow it.
Three of the daily direct trains are EuroCities which stop here in Saarbruecken on their way from Frankfurt to Paris. These will presumably be replaced by French TGV trains when the new high speed line "TGV Est Europeen" is inaugurated in France in June 2007. (Germany as usual is lagging behind, so these trains will have to putter along at reduced speed as soon as they cross the border.)
Update: Saarbrücken is still nearly three hundred and fifty kilometers from Paris, just as it always was, but the travel time is now greatly reduced since the French railway system opened a new high-speed stretch of tracks called TGV Est Europeen running more or less straight east from Paris.
The arrangement between the French and German railways is that the French TGV trains (meaning Train of Great Speed) use these tracks to connect Paris with Strasbourg, Karlsruhe and Stuttgart, with one train per day going all the way through to Munich.
The German InterCityExpress trains (ICE) use the same tracks but then veer off to the north to serve Saarbrücken, Kaiserslautern, Mannheim and Frankfurt am Main. Most of these ICE trains are non-stop between Paris and Saarbrücken, meaning that after leaving the Paris East Station they don't stop on French territory at all.
As of 2009 there are five of these ICE trains per day, making the run from Paris to Saarbrücken in less than two hours. This makes Saarbrücken the German city that is fastest to reach by train from Paris.
The drive from Saarbruecken to Merzig is about 50km. In Saarbruecken drive to junction Wilhelm-Heinrich-Bruecke/Stengelstrasse/Wilhelm-Heinrich-Bruecke, take left turn to A620/E29.
Follow directions: Saarlouis, leave Saarbruecken, continue ahead onto A620/E29, at the junction Saarlouis change onto A8/E29.
Follow directions: Luxembourg, Merzig, Dillingen-Mitte, at junction Merzig/Merziger Strasse turn right from A8/E29, continue ahead onto L173
Often use local transport for a "sightseeing" trip. One tramline runs through Saarbrücken, we joined it at the main railway station and stayed on it to the end at Sarreguemines, just over the border into France. Journey time around 30 minutes each way. On a cold and wet day a good afternoon trip.
Saarbrucken does have its own airport but I think it is for flights within Germany. From the UK I flew into Luxembourg which is just a short drive away - this was the most convenient way I could come up with for getting there.
In 1997 the first line of the Saarbahn was opened. This is a modern light rail system which runs through the city streets like a tram or streetcar, and switches to normal railroad lines out in the countryside.
Line number 1, shown in the photo, runs from Saarguemines, which is across the border in France, by way of Saarbruecken to Riegelsberg, a distance of 25.5 kilometers. An extension is now being built from Riegelsberg to Lebach, so the complete distance will be 44 kilometers.