Variants
editBatches 1–5
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The first four 721 series batches were built between 1988 and 1991, consisting of 22 three-car sets (F-1 – F-22). In 1992, in preparation for the Chitose Line extension to New Chitose Airport Station, a fifth batch, comprising 7 three-car half-sets (F-23, F-101–103, F-201–203), was built and arranged to form six-car sets. Fourth-batch set F-22 was combined with set F-23.[1]
From 2001, these sets (excluding sets F-1 – F-14) were upgraded to allow for 130-kilometre-per-hour (81 mph) operation. These sets are designated as 721-3000 series (721系3000番台).[1]
Batches 6 and 7
editThese batches were introduced between 1993 and 1994 and feature GTO thyristor-based VVVF traction control, comprising 9 three-car sets. They are designated as 721-1000 series (721系1000番台).[1]
Batch 8
editReferences
edit- ^ a b c JR北海道721系の番台別特徴と輸送形態 [JR Hokkaido 721 series]. Japan Railfan Magazine (in Japanese). Vol. 50, no. 585. Japan: Koyusha Co., Ltd. January 2010. pp. 42–47.
- ^ JR北海道721系デビュー [JR Hokkaido 721 series debut]. Japan Railfan Magazine (in Japanese). Vol. 28, no. 332. Japan: Koyusha Co., Ltd. December 1988. pp. 60–64.