The 23:57 is completely sold out. No possibility to board, you can ask railway staff if there are no shows. But you’lld better put effort in finding a hostel in Hamburg

Some option for the earlier night train though, at 22h01 (if you can make that). Book Asap via www.sj.se, add Interrail as a discount in the passenger details.

Where are you trying to book and for which date? You should check on https://www.snalltaget.se/

If it's full, then it's full though. There would then only be a possibility to travel with it if there's a no-show.

Thank you both! I’m trying to get on the train that leaves tonight aug 7th at 23:57. As @BrendanDB said I might be better off booking a hostel for the night if I can find it, but I’ll ask staff for no-shows first. As for the earlier option, I don’t think that’s a possibility given that the train I’m on toward Osnabrück was delayed at Amsterdam. Unless the transfer at Osnabrück - Hamburg is also delayed, I might get there later than planned (which still would have been too late for the 22:01). 

So… what was the original plan then? Please note that when you are stranded because of railway delays and cancellations, the railways are obliged to assist with overnight accommodation and (if needed) a ticket for the continuation of your journey without extra costs. for you. If this applies to you, then speak with the DB staff, already on the train or at the latest in Hamburg.

Original plan was a long journey from Amsterdam C to Oslo S, with the 9hr night train from Hamburg Hbf to Lund C being the deciding factor. As the seat reservation on this connection became full, I’m now trying to find another route before my pass expires on midnight of Tuesday the 8th. 

Not sure I could make the argument that I became stranded due to delays, since the only delay so far has been the Amsterdam-Osnabrück connection (although I WOULD have missed the Hamburg-Lund connection at 23:57 if I had the seat reservations).

In any case, now I just need a way from Hamburg to Oslo. Booked hostel for tonight (aug 7-8) in Hamburg. Currently trying to find a way to continue the journey tomorrow at dawn. 

Lesson learned: last-minute reservations are not a smart idea…

The direct trains to Copenhagen are sold out in 1st and 2nd class since it's a very popular route. Here is a connection that works (pretty much the only one) :

- RE Hamburg Hbf - Flensburg 06:40 - 08:40

- IC Flensburg - Fredericia 08:48 - 10:14

- IC Fredericia - Copenhagen 10:23 - 12:03

Those 2 trains can be bought with DB for 4.90€ (recommended).

- R Copenhagen - Mölndal 13:27 - 17:10

- Bus Mölndal - Göteborg 17:20 - 17:40 (engineering works, pass valid)

- IC Göteborg - Oslo S 18:10 - 21:42

You could also take a look at taking a ferry between Hirtshals and Kristiansand/Larvik. EDIT : Looks like the ferry journey is not possible in a day due to bad timetables...

EDIT : the Osnabrück - Hamburg train is delayed by 13 min so you'll probably make that connection.

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Yeah, the Osnabrück-Hamburg train was delayed until 21:23, so I’m sitting idly by for now. 
 

I’m eager to see if I can make all those connections! Will certainly try. Thankful for all the good tips and effort put into the write-up- makes a lone traveler feel a little less alone when things go awry. 

There will be strong winds in the southern part of Sweden tomorrow and some trains over the Öresunds-bridge will be cancelled.  I recommend you to check at sj.se for the trains from Copenhagen to Mölndal. Take the earliest possible Öresundståg across the bridge once you have reached Copenhagen.

It is better to wait in Malmö than to wait in Copenhagen as there might be a risk that the bridge closes for all traffic. 

Thank you! I made it to Copenhagen just now. Managed to speak to a train official after arriving in Hamburg and taking the direct train (per his advice) - thankful for an early arrival. Booked the Öresundståg to Mölndal at 08:27. Thank you again for the follow-up!