This train can't be booked online for pass holders.

Book at a station that can do international reservations.

Yes i tried to book a reservation at  warszawa centralna station. My trip starts next friday, but there is no place available anymore.. i wonder what Will happen if I step on the train whithout a reservation? 

Better late than never.

Don’t know what train type it is, I went few day ago only for Kaunas (Warszava Centalna <> Kaunas with change at Mockava station via IC144 > T135).

Had reservation without seat number  - as stated in area marked red (acquired from web page).

They have no reservations for me for whole route via any channel (IR page, PL page) as well so I looked at itinerary of the train where seat are requested (don’t know how many trains you go and if all of them need to be with reservation) and made one for the very last station before borders.

In train none checked it - only IR Pass. My train almost half empty all the time. Almost full only for few first statitons.

In this case depends on how many ppl is aboard > whoever have reservation will push you out, so in need to find new place or stay in aisle till next place is free.

Luggage can remain where left depends what the other persona will have with them and if they fit it in the storage rack above seats.

Saw few ppl roaming like this - they were leaving seat cos no reservation with them. All locals - so it’s possible to board the train without it I think.

Hope you made it.

Dear Mice, thank you for your reply.

We booked a plane. As we are 69 and 70 years old we could not risk standing up all the time. This is our first time travelling by train. It was really impossible tot book any reservation for the connection Warschau - Vilnius. I tried months before via internet and later on also in Berlin trainstation and Warschau trainstation. So I think things are due to improvement!

In the mean time we visited Vilnius, Riga and Tallinn and are now sailing tot Helsinki. We learned a lot this trip. 

Hope you have a great trip too.