I'm a bit surprised nobody has mentioned this yet, but glad that I for once have some additional context to offer. These jingles are composed by Minoru Mukaiya

I'm a bit surprised nobody has mentioned this yet, but glad that I for once have some additional context to offer. These jingles are composed by Minoru Mukaiya. He's mostly famous for being the main keyboardist in Casiopea, a very famous Japanese fusion jazz band. He was the keyboardist until the band went on hiatus in 2006, 29 years in all. His style can clearly be heard in these jingles and he apparently has always had a thing for trains anyways as he went on later to start up a train simulator game company.