Please don't use the rail planner app or Interrail website to plan. They don't get updates frequently enough to be reliable. It's much better to use national or local websites and apps. For international planning, the DB website or DB Navigator app is a good choice.

The DB website already contains Öresundståg also after 10 December, so I suppose the rail planner app will also have it with its next update.

Further, reservations for Sweden are best made via on sj.se. Via Interrail it's more expensive.

The Railplanner is not working online so always use the planner of the national railway for your detailed planning. See more information below. 

Here is some useful information from the experienced travellers in the Community regarding both planning, reservations and activation of pass and travel days. 

 Planning

The rail planner is normally not up to date, as it only is updated once a month, so to be sure of the time table you better check the timetable and availability on the websites of the national railways. The bigger national railways, like DB (Germany) SBB (Switzerland) and ÖBB (Austria) cover several countries. 

 Reservations 

When/if you make reservations through sj.se it is important that you don't mix SJ-trains and trains from other operators. If you do that SJ will charge a full price ticket for the non-SJ operator even if you should travel for free on that train with Interrail.  

Thank you for the quick replies.

I understand that I should use the local planners, but the rail planner has the advantage that it tells me if I am required to make a reservation on top of my interrail pass.

For example if I would use the SJ to plan my trip I would have to pay for a reservation for the Öresundståg, while the rail planner says I can board without one. 

So I suppose I'll just need to use both. 

But even the rail planner app is mistaken sometimes in what needs a reservation. Google and this forum always help out too .

Weird that the SJ app says you need to reserve the Öresundstaag, sure it’s not the ordinary ticket price? -Although there are a few reservable seats on those trains. But the whole lot of it is just free seating.

@BrendanDBsj.se behaves very strangely when it comes to trains not operated by SJ. Interrail reservations can’t be made through the SJ app, but they have to be made at sj.se. There is no info in the timetable at sj.se about which trains that have mandatory seat reservations.

An example of the strange behavior is that if you want to make a reservation on Öresundståget, which you might want to have if you are traveling from Göteborg to Malmö in rush hour, you need to actively select what type of seat you want to have. If you don’t do this selection you will end up paying 30 SEK for noting as you would’t get an assigned seat.

I just saw I misspoke, I can't make a reservation through the SJ website for 2nd class.

But I did check the price for a normal ticket (~150 SEk) and for one when you say you have an interrail pass (~35 SEK). Quite confusing, but it's not a high-speed train so I think I can just hop on.

Are SJ aware already of that? In fact, that's providing false information and making people pay too much, which is not allowed.

You don’t need a reservation for Öresundståg. In Sweden you need reservations for the high speed trains (SJ Snabbtåg), the IC trains and the night trains. All SJ regional trains are reservation free and all other included regional trains are reservation free.

What route did you want to make a reservation for and didn’t succed?

I don’t know if SJ knows this, but it is commonly known in the Swedish Facebook group for train travels.

I'm not trying to make a reservation, I'm all good . I was just talking about the cost SJ makes you pay eventhough with interrail the trip should be free. For Lund to Copenhagen.