2:36 I think, that this announcing system is also in buses. 8:28 I remember, when I was younger, that this chime was also used in Mobilis' buses in Krakow from 2008 to 2014 (when they had Irisbuses, Solarises, and, around 2013/2014, MAZes and Solbuses). For announcing, they used male voice (different than current one (in case of operator) or the MPK ones (including current one, Damian Galon), which looked like elderly person's one). I used this operator to go from my preschool (at Młyńska Boczna street) to Maltese Cross Centre at Chestnut Alley (polish: Aleja Kasztanowa). Today, this chime is still used in some other polish cities.
2:36 It was a different voice on trams and trolleys back in 2019. Now, they use the same voice on all their modes of transport. 8:28 Yes that chime is quite common.
1:51 is voiced by Acapela-Rasmus. The jingle at 1:54 is originally composed for the station announcements at Praha Hlavní nádraží, and I'm pretty sure this isn't a stock jingle. So I guess Start got the rights to use the jingle...
That is indeed the former jingle of Praha Hlavní nádraží and I don't have a clue why Start is using it. It is adpated from Bedrich Smetana's Vyšehrad: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-trgCZrgL4Ws.html