Hello.
What is the name of the bus service to El Escorial and how much is the ride?
I don't know about the bus.............but we took the train from the Atocha station in Madrid. Not too long (maybe one hour?) and then a longish walk thru a lovely park to the monastery. There may have been a local bus available, but we walked both directions.
It's an amazing place.
Hotel Europa emailed me the entire train & bus schedule (we are spending the night there). I'll scan it in & send it to you.
http://escorial.banesto.eurociber.com/i9700020.htm
Here's the link for train & bus info for El Escorial