Transition is a web based transit network edition and analysis platform. Leveraging OpenStreetMap data as it's base data source, it lets you create a network from scratch easily or import and modify an existing one via GTFS files. You can create multiple scenarios and compare them via various visualisation Using travel survey data, we have a genetic algorithm that can optimise your network, reducing overall transit time for users, while keeping your constraints fixed. The talk will present the various features of the platform, with examples from actual cities, describe our routing infrastructure, show where we are hoping to go and touch the topic of OSM data quality and the data require for best analysis. This is a great example of a project who started in the depth of a research lab and graduated to be used outside of it. The development was done in collaboration with planners from various transit agencies, which insure that the features are useful to users. We could tell many stories about the challenges of bringing code from the research labs out to the real world, we'll touch on some, time permitting. We developped our routing engine for transit purpose, trRouting. We also build on top of OSRM (Open Source Routing Machine).