Need help to travel in trains in Kerala.

I'm born and brought up in Bombay but my native place is kerala. So in Bombay we have these apps like m-indicator(it shows timings of local trains etc) and UTS which is very helpful for booking tickets. What would be the equivalent of m-indicator but for kerala? And How can I travel from kollam junction to kundra station by train around after 3pm today(29th dec)? As it's showing on some websites to take either an express train or MEMU train, My doubt is, Can I buy an ordinary ticket or express ticket in general class as it's just 20-25mins distance or will I have to book a whole sleeper seat for the travel? Any and all help is appreciated! Thanks.