The magazine "Travel and Railways" is conducting an online survey of railfan favorite/most popular private/third sector railways. The voting began on March 22 and will last until April 20. Final results will be published in the July issue of the magazine, on the newsracks May 20.
As of April 15 JST, the most popular railway is Keikyu, with Hankyu coming in second and Kintetsu third.
https://www.tetsudo.com/special/tabitetsu/