While three of the Delhi Metro's busiest corridors offer free Wi-Fi at all stations, commuters are expected to have access to free high-speed internet onboard trains across the network by next year. The Delhi Metro Rail Corporation (DMRC) must overcome a few obstacles before the plan can be implemented. In January of last year, DMRC managing director Mangu Singh launched a free Wi-Fi service for commuters riding the Airport Express Line's high-speed trains. The same service was to be provided in all trains and stations across the network. The service was previously available at stations on the Blue Line (Dwarka-Vaishali Noida Electronic City) and, more recently, at stations on the Yellow Line (Samaypur Badli-HUDA City Centre). A DMRC official told the media that the corporation provides space and basic infrastructures, such as optical fibre and power cables, as part of an agreement, and that the rest of the infrastructure must be installed by telecom service providers. Wi-Fi was first made available at the Airport Express Line's six stations in 2016, then at all Blue Line stations in 2017, and most recently at Yellow Line stations. The Airport Express Line uses a two-level network to provide commuters with access to WiFi at a speed of 300 Mbps on-board moving trains. For starters, it's a train-to-tunnel radio network that sends signals from tunnel base stations to portable base stations in head cars. Second, there's the inner-train network, which sends signals from each car's wireless access points to users' devices. Wi-Fi was first made available at the Airport Express Line's six stations in 2016, then at all Blue Line stations in 2017, and most recently at Yellow Line stations. The Airport Express Line uses a two-level network to provide commuters with access to WiFi at a speed of 300 Mbps on-board moving trains. For starters, it's a train-to-tunnel radio network that sends signals from tunnel base stations to portable base stations in head cars. Second, there's the inner-train network, which sends signals from each car's wireless access points to users' devices. Image SourceAlso read: Delhi metro rail to use conventional trains on metrolite corridor