After the establishment of JR West, the increase in maximum speed up to 160 km/h on the Kosei Line and within the Hokuetsu tunnel was examined, and at the same time the JR (West)/Hokuetsu Express' Limited Express Series 681 was manufactured as part of the plan; however, because of high costs for the improvement of railroad signals (e.g., installation of six-light signals on the Hokuetsu Express Hokuhoku Line) and the existence of low-speed local trains or freight trains and passenger trains pulled by electric locomotives, the travel time was estimated to be shortened by only 5 to 10 minutes, and consequently the operation at a maximum speed of 160 km/h was called off due to the low cost-effectiveness.
JR西日本発足後、湖西線内と北陸トンネル内にて最高速度を160km/hに引き上げることが検討され、その一環としてJR西日本681系電車が製造されたが、日本の鉄道信号機改良（北越急行ほくほく線のように6灯式信号機の設置）等のコストが嵩むこと、一方足の遅い普通列車や電気機関車が牽引する貨物列車や客車列車が存在することなどにより、結果として5～10分程度の短縮にしかならず、費用対効果が薄いと判断されて見送られるに至った。