Renfe trains - lead time at station?

The larger, higher security stations recommend arriving 30 minutes before departure. You will need to pass your bags through an x-ray machine before you can enter the waiting area, and when they call your train you will queue up to get your ticket checked before boarding. The Madrid train stations are quite large with many platforms for different types of trains so it may take a while to figure out where you need to be. Barcelona is easier to navigate. Stations in smaller towns have fewer passengers boarding and may skip the bag screening so you don't need as much time there, 10-20 minutes should be plenty.

30 minutes is correct. Also keep in mind that they stop boarding about 5 minutes prior to departure. The security screening only takes a few minutes and is minimal compared to airports (it happens as you enter the train platform, not a waiting area).

as the other posts, I agree 1/2 hour is about right. And remember, the trains leave on time!!! The coach number and seat number will be on the ticket. If you have any question, someone will be there to assist.
Remember also there are two stations in Madrid - Atocha and Charmartin - and on opposite ends of the city. Enjoy the rides!

Thank you! I know for my first trip I will need extra time to find my way, but that gives me a level of comfort to know the "standard" security/boarding times.

Douglas, our experience in May was that the xray machines at Atocha and Barcelona were placed so that we had to screen our bags before entering the waiting lounge. At smaller stations the machine usually was at the platform...in Jerez it was in the station but they weren't running it when we arrived. We also noticed that an attendant will sometimes help to put the bags on the belt if the traveler appears to be struggling, which I don't see at airports.