The main diesel locomotive of JR, which is still used in the San'in Main Line, is a model called Class DD51. This locomotive is a diesel-hydraulic locomotive, not a diesel-electric locomotive.
国鉄DD51形ディーゼル機関車 - Wikipedia
Anyway, we call it "kisha" even if it doesn't use steam, and the writer no doubt used "kisha" as just train
here, not as steam train.