The only reliable thing I can think of is the Osaka Municipal Transport Bereau. They have a dual language website here:
http://www.kotsu.city.osaka.jp/index.html on which you can look up the schedules direct if your japanese is good enough. Sadly the english section only talks about the subway BUT, failing that they have an office you could go to in person or call and ask, it's in Namba.
＜Subway Namba Station＞
(06) 6211-9503
Weekdays ： 9:00～19:00
Sat., Sun., & Holidays ： 10:00～19:00
Information is available regarding the Osaka Municipal Transportation services (subways, New Tram and city buses), tickets and more.
And it says they provide information in English as well. Hope that helps
