The appearance of new alternative fuels for urban fleets has motivated the developing of a new methodology to plan the fuel supply infrastructure required to cover the new demand. The fuel cell hydrogen vehicle has been identified as the alternative with the greatest possibilities in the medium to long term to replace conventional vehicles. In order to make easier and cheaper the implantation of the new supply infrastructures, it is necessary to develop analyses which allow us to determine the design, size and so on. This research shows an analysis and a tool which allow us to approximate the design and size of a new hydrogen distribution infrastructure. To calculate the parameters needed to introduce in the infrastructure, the number of vehicles, the hydrogen consumption of these vehicles and the technology utilized to supply the hydrogen are taken into account. One of the most important considerations to determine these parameters is the hydrogen delivery system that is going to be used for the hydrogen fuelling stations. With the objective of validate this tool, a case study has been defined. This case is based on the implementation of a tram line powered by hydrogen. It is also defined, the requirement regarding to the necessities and the hydrogen supply infrastructure. The most important variables are the cost, demand, location of facilities and security of supply. Due to the big amount of parameters and variables this tool could be a good decision support system to help to delimit the size, cost, design…of this particular kind of infrastructure.