SJ Regional

SJ Regional is a service rather than a specific type of train and as a result three types of train are used for these services:

(1) the double-decker
(2) the Regina
(3) the X 12

What all SJ Regional trains have in common is that no catering is available on board.

Seat Reservations:

If a double decker or Regina train is being used for your journey and you book a 1st class ticket, a complimentary seat reservation will be included with your ticket purchase.

If you book a 2nd class ticket, you can opt to add a reservation for an additional cost of 50 kr.

You can find a little more info on the SJ Trains Guide.

An intro to train travel in Sweden

How to buy tickets for Swedish train journeys

International train routes to/from Sweden

Travelling on European daytime trains

Travelling on European overnight trains