Reservations for that service are not required but are available.

There are other sources than the eurail website that will be cheaper for reservations, the obvious one being bahn.com

There should be a little symbol in the train description, shaped as the outline of several persons, the more that are solid the busier the train is expected to be.

I'm guessing this is the connection you'll be using:

On this day, low demand is expected. Making a reservation in 1st class will cost €5.90 via DB, or 3€ via ÖBB or CD.

Eurail charges an extra fee of 2 EUR per person and train so if possible it is better to make the reservation, if you want one, elsewhere. Please read more about this 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 

There is no need. BUT in 1st all normal tickets get a free RES with it and this may mean that even when you sit your seat can be assigned to someone just booking for onward in that trip-though in this case it is so short it hardly matters. It also means that the seats are not always marked as they usually are for RES from A to B-so you can check. Regular 1st class (beezneez) people are quite well used to this fenomenon of the quite different looking EUrail-but not all. And they can also get sniffy.

PS-there is NO free food/drink at all in German ICE-what looks like that is a special ´on seat´ service-payable-for 1st cl and a kind of tip-bringer for staff. You will also have NO access to its special 1st cl lounges with pass. This is specific for DE=Germany (from where I returned myself yesterday)

I'm guessing this is the connection you'll be using:

On this day, low demand is expected. Making a reservation in 1st class will cost €5.90 via DB, or 3€ via ÖBB or CD.

Thank you! You are a godsend! This helped soo much! I was reserving seats at eurail.com and it’s a great resource, don’t me wrong. But paying directly at OBB or the Czech (CD) train website is wonderful, especially when you’re crisscrossing Europe and things get expensive real fast; saving here and there, even a little bit, adds up in the end.

I spoke to DB and OBB on Twitter and they said the Berlin to Hannover is in high demand during those morning times and can get full. They had advised me to try to reserve a seat a few days before or the night before at the latest. I know it’s just recommended and not required but I didn’t want to take any chances and I paid the 3 Euro for the seat reservation.

I should also mention my Eurail Mobile Global Pass is for 1st and 2nd class for the flexibility. I don’t know how much that matters if I happen to catch a train without a seat reservation. Would they throw someone off who has this Global Pass with 1st class but no seat reservation because they are at capacity or would they find somewhere for me to sit?

Thanks again for your help!

If the train is too full, all people without reservation have to leave the train. 

Thank you for the link! My goodness, there are endless resources to buy tickets that it can make your headspin. Seat61.com has endless resources on trains, as you know. And I discovered there are holiday/vacation tour website businesses that book train and destination packages for you, all inclusive. You pay more for the hands-off approach but it might be worth the hassle and you’re saving time.

And I did see the the outline of persons to indicate how busy the train is. Thanks for describing that so well! 

Thank you for that link! Yes, I have looked through it and it’s quite an exhaustive list and filled with many different tips and tricks. Yes, I’ve followed the lead from here and booked directly from DB, OBB, and CD websites, thus far.

It can be wise to make a test and activate the pass with a start date well in the future and then deactivate the pass immediately, just to see that everything works.

Can you please expand upon this thought? I’m not sure I quite understand. I have to search for the email from Eurail but, if I recall correctly, what I was told by Eurail is once you activate the pass, you can’t exchange or refund it. Only a non-activated, unused pass can be refunded or exchanged. In my case, I purchased a 2-month unlimited Mobile Global Pass Plus with 1st and 2nd class seating.  The Plus makes it 100% refundable and exchangeable before I travel. So, what you’re saying is that I could activate it, then deactivate it right away (for the test) and the pass would be still 100% refundable and exchangeable? How would I activate and deactivate in the app? It’s a great idea to make sure everything works.

The advice from the experienced travellers in the community is also never to activate a travel day, that is connect a journey to your pass and create the ticket (QR code)…

By “connect a journey”, you mean where you add your travel itinerary under “My Trip”. I thought that was just for your sanity so you know where you’re traveling and on what day. Simply showing the train conductor that you have a Eurail Global Pass is not sufficient then? Are you saying I must create a journey under “My Trip” in order to create the ticket (or QR Code) and that is what I would show the train conductor, not that I’m using a Euro Global Pass, is that accurate?

I was thinking the Euro Global Pass is similar to a monthly metro or regional train card that you’d show the train conductor as he/she walks by to check tickets. I guess it doesn’t work exactly like that then.

Thank you for your help.

Having experienced a very busy ICE train, fortunately with a reservation, I applaud your wisdom in getting a reservation.

Although some reservations are expensive (and usually mandatory) these low cost reservations take a huge pressure off your journeys, especially in first class where seating capacity is a fraction of second class - maybe as little as 10% of the train’s full capacity.

Personally I will always travel with a first class pass, even if the train only has second class seats (most regional and local trains). The extra space and normally a bit more tranquillity is welcome.

On your final question you are correct that your pass works differently to those where you just show them.

Your mobile pass has three main sections, Planner, Trip and Pass.

Although not the greatest tool for planning you use the planner to find your journeys, which may range from one to several connected trains. You can transfer any of these to your TRIP.

You can also add individual trains manually to your trip, but as long as your planned trip shows in the planner it is better to transfer from the planner.

Your trip is simply a diary of your planned trains and can be added to and deleted from at will. In no way does a train listed in your trip entitle you to travel on it. For that you transport it `to your pass by operating the little slider. Until you board your train you can always remove a train from your pass back into your trip by reversing the slider.

The first train on any day that you add to your pass will create a travel day which shows the train details, plus those of any you subsequently add for that day.

Then you open your pass, select your travel day and you will see a button marked “show ticket”, Pressing this will create a QR code for the day along with your train or trains for the day. That is your ticket for display when required plus any reservation document.

You can add as many trains as you want in a day, but they must be in your pass before boarding or soon after.

Interesting. So, let’s say I’m taking a train from Berlin to Hannover. I board the train at Berlin. I don’t have a seat but I have my mobile global pass. During one of the stops in-between, people enter the train and the the conductor discovers the train is full but these people have reserved seats. Can and will the conductor come to someone like me, who has the global mobile pass (1st and 2nd class) but no seat reservation and kick me off on my way to my final destination? If yes, that lends evens more credence that I should purchase seat reservations during my travels just to be safe and not leave anything to chance.

Hmm. Just to clarify, you’re saying all 1st class tickets purchased on, e.g. OBB, SBB, DB, get a free seat reservation with it (which makes sense) or are you saying that a Eurail Mobile Global Pass with 1st Class and 2nd Class will permit me to sit in 1st class and, therefore, I inherently get a seat reservation?

And you’re saying that even if I purchase a separate seat reservation in 1st class or not, it is possible to reserve a specific seat by someone else and the conductor has a right to move me to another seat, is that right?

Thanks for the tip at the end there. There are quite a number of nuances with train travel throughout Europe. Almost as if you can build a business model around it. :)

Yes, you can be none too careful. I don’t feel good about leaving things to chance, especially traversing throughout Europe. Failing to prepare is preparing to fail. For all my travels, I’m purchasing 1st class seats or whatever is available. Yes, the extra space afforded might be a welcome retreat for the weary traveler, definitely good advice, thank you!

No. If you get a reservation it will be for a specific seat for the journey you requested, nobody else will be assigned the same seat and you will not be asked to move in preference for someone else.

The previous quote about non-reserved passengers being asked to leave only applies in extreme situations with large numbers of people standing.

Given that bahn.de advises low demand for your trip, I would just relax and get on with other things.

You will be fine.

Be aware that this summer has seen huge demand for ICE services in Germany:  partly because of the 9 Euro local ticket promotion, partly because everyone wanted to go on holiday at once after a quite difficult winter and partly because Germany airports have had very big problems with security/check-in and so on.  The result has been hugely crowded trains, big delays in many parts of the network and frustration for both staff and passengers.  But things are calmer now, schools have restarted, and the 9 Euro ticket promotion is ended.  So some of the chat posts you see are really because of the problems this summer, which indeed has been a very difficult one for many rail travellers.