Dataset colection of weighted graphs
For any problems involving graphs for which you need test data you can use Knuth's less well known work 'The Stanford Graph Base'. This includes many data sets designed to test all kinds of graph problems. The materials are described at https://www-cs-faculty.stanford.edu/~knuth/sgb.html and are available for download at ftp://ftp.cs.stanford.edu/pub/sgb/sgb.tar.gz