Through Service with Subway:
There have not been many changes in the Tokyu network since the opening of the Shin-Tamagawa-sen in 1977, although it has become a lot more efficient, especially by extending train lengths and increasing train frequencies. But as traffic is growing year by year, more must be done. One of the biggest problems is that the capacity of Shibuya station (Toyoko-sen) can hardly be increased, neither can the number of trains on this line. To relieve the congestion at Shibuya station (and also on the Ginza subway line), through-running with the subway Hibiya-sen had already started in 1964. The trains leave the Toyoko-sen at Naka-Meguro, two stops before Shibuya, and then go underground to central Tokyo, but this route has now also reached its capacity. The through service of the Shin-Tamagawa-sen with the Hanzomon-sen had started in 1978 relieving some of the pressure on Shibuya. A similar service will start around 1998, when the subways Namboku-sen and Mita-sen will be extended from their current termini at Komagome and Mita to Meguro to connect with the Mekama-sen there.

Toshin (City-center) sen:
Tokyu's new Meguro station is now under construction; it had been parallel to JR s station since 1923, but will become an underground station to enable through-running with the Namboku-and Mita-sen. Much must be done on the Mekama-sen, as there are today only 4-car-trains running on the line, and the cars are just 18 meters long. The line will be completely rebuilt between Meguro and Denen-Chofu, to take the standard train size of 8-car-trains with 20-meter-cars. New underground stations at Ookayama and Denen-Chofu are already being built with better connections to the other lines. The track on the Toyoko-sen will be doubled between Denen-Chofu and Hiyoshi to make trains faster, but this is also necessary to get more capacity. Today there are only trains from Hiyoshi to Shibuya and into the Hibiya-sen, but in a few years it will be possible to ride through to the Namboku-sen and Mita-sen without changing trains. Then Tokyu will have through-running with 4 subway lines, more than any other railway in Tokyo. An interesting fact is, that the Namboku-sen and the Mita-sen will share the new subway tunnel between Seishoko-mae (under construction) and Meguro. The two subway lines belong to different companies (Eidan and Toei), that have never had the joint use of any of their facilities.

MM21:
There will also be big changes at the southern end of the Toyoko-sen. The construction of a new city center southeast of Yokohama station, called "Minato Mirai 21" (MM21), brings the need to build a railway there. Therefore, the Toyoko-sen will be moved underground between Higashi-Hakuraku and Yokohama (2.1 km, including a new underground station at Yokohama), and the last part of the Toyoko-sen (2.1 km between Yokohama and Sakuragicho) will be closed. All trains on this line will then (maybe from 2000) continue on from Yokohama over the new line, which will be 4.1 km long and have stations at Minato-Mirai-Chuo, Kencho-mae and Motomachi. Only Tokyu trains will run on this line, called MM21-sen, but the owner will be a new company, Yokohama Kosoku Tetsudo (Yokohama High Speed Railway). This company is a joint venture between the city of Yokohama, the prefecture of Kanagawa, Tokyu, the Japan Development Bank and Mitsubishi.