A technopop tune that even the toddlers would love, which would explain why it got heavy rotation on the Fuji-TV kids show "Ponkikies"（ポンキッキーズ）. When I had the morning shift at NOVA or at my other school, I would have to get up somewhat early and have breakfast while catching a bit of the program. Some time during the half-hour program at 8 a.m., there would be a song of the day which is why I came across "Popo".
I always thought Denki Groove（電気グルーヴ） was a unit that also had a quirky sense of humour, and probably for that reason, some of their creations would have been approachable for the elementary school set. "Popo" just came on in its 1-minute version on "Ponkikies", but it was instantly catchy, and what kids wouldn't love to get on an old SL and become the engineer? Released in November 1994, it was the band's 4th single and was created by members Takkyu Ishino and Pierre Taki（石野卓球・ピエール瀧）. The above is the full version.
The above link will take you to that one-minute version I used to see weekly on the show. I had forgotten how fun and funky the video was. The song itself got as high as No. 12 on Oricon and it was also part of Denki Groove's 5th studio album, "Dragon" which came out in December 1994.
The above is a little treat. As I said, a number of cute songs was part of the Ponkikies discography, and here is another train-themed one that I often caught. The two performers here were just teenagers at the time, but one is future actress/tarento Ran Ran Suzuki and the other will become even more famous. See if you can recognize her (just go to 20:10).