稼働 and 運転: Running Devices and Temporarily Suspended Train Service
Compare a repaired machine and three devices running together with driving to work and train service suspended by snow. Preserve the operating object and simultaneous or temporary timing.
Operation after repair and three devices running together
稼働 (かどう) means operation or running. 「修理を終えた機械が再び稼働しました。」 — “The repaired machine resumed operation.” The machine resumed operation after repair was finished, rather than being described as running during repair.
「工房では三台の装置が同時に稼働しています。」 — “Three machines are running simultaneously in the workshop.” Three devices are currently running together in the workshop. 同時に gives simultaneous activity, without stating a sequence of switch-ons or an exact starting time.
Driving a car and suspended train service
運転 (うんてん) means driving or operation. 「父は毎朝車を運転して会社へ行く。」 — “My father drives to work every morning.” The father drives to work every morning.
「大雪のため列車の運転が一時止まった。」 — “Heavy snow temporarily suspended train service.” Heavy snow temporarily suspended train service. 運転 therefore is not limited here to a person's driving action. The sentence does not add permanent closure or a service already resumed.
Operating objects and two different time relationships
The 稼働 examples concern a machine and devices. The 運転 examples concern driving a car and train service. Keep operation resumed after repair separate from operation during repair.
同時 gives the devices' simultaneous operation; 一時 gives the temporary scope of the train-service suspension. Preserve concurrent activity rather than a sequence, and temporary suspension rather than permanent closure.
How do 同時に for the three running devices and 一時 for the train-service suspension differ?
Show the answer and why
The first describes three devices running simultaneously; the second describes a temporary train-service suspension. Neither a sequence of operation nor permanent closure is added, nor are exact device start times or a train service already resumed.