On July 22nd 2018 the Noord/Zuidlijn, a metro line crossing the city center of Amsterdam, became operative. This entailed a transformation from a direct bus and tram network to a network consisting of a metro trunk line and bus and tram feeder lines. This study explores and uses interoperable smart card data from before and after the Noord/Zuidlijn became operative to measure the regional travel time and transfer impacts of this network overhaul. On a working day on average 1,350 hours of travel time are saved. The travel time savings and losses are 2,350 and 1,000 hours per day respectively. Additionally, 2,500 extra transfers are made per working day. The transfers gains are 4,500 transfers and the transfer losses are 7,000 transfers per working day. 20% of the travelers experiences a decrease in travel time of more than 1 minute, 10% experiences an increase in travel time of more than 1 minute. Furthermore, interoperable smart card data showed to be promising as it captures travel behavior across multiple operators. However, the fact that the number of travelers is given in bins complicates analysis. This study develops a methodology to work with interoperable smart card data. Additionally, as only few studies have evaluated the transportation impacts of a large-scale public transport network overhaul ex-post, the findings of this research could improve public transport planning and assessment.