As far as I can tell*, this train consists of around 4 second-class carriages, which each consist of closed, 8-seat compartments. (One second class carriage also has a baggage compartment, and there's one carriage which is half first-class, half second-class). All the compartments should have fairly spacious overhead luggage racks, and possibly also a bit of space under the seats. I don't think that there's any additional baggage space at the end of the carriage. (In the past, I've also seen some open saloon carriages used on these trains. These also have fairly spacious overhead luggage racks, plus some space between the seatbacks - I'm not sure about space at the end of the carriage). Anyhow, your bags should easily fit on the overhead racks, but if the compartment isn't crowded, you can also leave them on the floor.

* www.cd.cz will show the composition of trains, but only for journeys entirely in Czech. So, looking at Regensburg-Prague, it won't show the train composition. However, if you check the 12:10 EX355 'Albert Einstein' departure from Domazlice to Praha (ie: the same train you'll board earlier on in Regensburg) it will show the composition. By default, the logo for second class carriages means 8-seat closed compartments, unless there's a "two seats" logo superimposed on the carriage, in which case it's an open saloon.


I didn't think they were, but the "Prague Special" ticket brochure says:I'm not sure if this means only for the part of the journey inside Czech, or only for the CD operated carriages (the train may have both ALX and CD carriages). Although it says VGB (ie: ALX, the operator in Germany) can't make reservations, it doesn't say how you can make them... You could try at the station in Regensburg the day before (or earlier) - but if that doesn't work, I wouldn't bother about it, and just go without reservations. (I suspect >90% of the other passengers on this train also won't have reservations).

The train may be somewhat full when it arrives in Regensburg, but will probably empty out as it approaches the border, and then re-fill as it approaches Prague. If you're in second-class, and look for a seat at the opposite end of the train from the first-class carriage, you've probably got the best chance of having space to yourselves (as the train will generally fill up from the middle).

The train has a ten minute stop in Regensburg (it arrives at 10:21 from Munich), but be aware that not all carriages may go through to Prague. It's possible they will split the train in Regensburg (or maybe in Schwandorf). So, make sure you get in a carriage that is going through to Prague - there should be a destination sign in the door for each carriage, so it's not difficult to ensure you've got the right one.

I'm not 100% sure for this route, but it may not matter that much.
For Prague-Berlin, the route from Prague as far as Dresden runs along the River Elbe, so it's clear that you want to sit on the river side (ie: right-hand side, in that direction). However, I'm not sure there's anything so specific for the Regensburg-Prague route.
Also, if you're in an 8-seat closed compartment, you won't have much choice - as only one side of the compartment has an external window - the other side has a window onto the corridor.