I introduced the outline of Keio's commuter train, EMU 7000 series, seven years ago. Today, I'm going to follow up and explain this model in more detail.
The 7000 series debuted in 1984 to enhance transportation capacity on the Keio line. A total of 190 cars were built until 1996 by Nippon sharyo and Tokyu sharyo. It's the first stainless-steel body train on the Keio line. The technical specification of the 7000 series was originally similar with that of the 6000 series launched in 1972. For example, both the 6000 and the 7000 series have the same field chopper electric control systems.
The early 110 cars of the 7000 series have corrugations on the side bodies. What for? It's for concealing the distortion on the stainless-steel plates. In the 1980s, even if skilled welders did spot welding for stainless-steel plates, they couldn't prevent distortion on the plates. The outer corrugation plates covered the welded plates for concealing the distorted parts. On the other hand, the later 80 units have bead-press stainless-steel bodies. As a result of technological progress, corrugation plates were no longer needed from the late 1980s. The bead-press body has a simple design without corrugation.
17 years after its debut, the renovation for the 7000 series was started due to the deterioration. For instance, the electric control system was changed from the field chopper to the state-of-the-art IGBT-VVVF (insulated gate bipolar transistor-variable frequency drive) inverter with induction motors.
The EMU Keio 7000 series... it's still active.
The 7000 series debuted in 1984 to enhance transportation capacity on the Keio line. A total of 190 cars were built until 1996 by Nippon sharyo and Tokyu sharyo. It's the first stainless-steel body train on the Keio line. The technical specification of the 7000 series was originally similar with that of the 6000 series launched in 1972. For example, both the 6000 and the 7000 series have the same field chopper electric control systems.
The early 110 cars of the 7000 series have corrugations on the side bodies. What for? It's for concealing the distortion on the stainless-steel plates. In the 1980s, even if skilled welders did spot welding for stainless-steel plates, they couldn't prevent distortion on the plates. The outer corrugation plates covered the welded plates for concealing the distorted parts. On the other hand, the later 80 units have bead-press stainless-steel bodies. As a result of technological progress, corrugation plates were no longer needed from the late 1980s. The bead-press body has a simple design without corrugation.
17 years after its debut, the renovation for the 7000 series was started due to the deterioration. For instance, the electric control system was changed from the field chopper to the state-of-the-art IGBT-VVVF (insulated gate bipolar transistor-variable frequency drive) inverter with induction motors.
The EMU Keio 7000 series... it's still active.
Official promotion movie, Keio Electric Railway (1):
Official promotion movie, Keio Electric Railway (2):