train schedules and pricing.

Generally, the official site of the country you are traveling in. Seat61.com will help you figure out most everything about trains in Europe.

I use www.bahn.de to research schedules between countries and in Germany. Otherwise, I go right to the country's train site, www.trenitalia.com or www.italotreno.it for Italy, www.sbb.ch for Switzerland, etc. You might also get a lot of info from www.TheTrainline.com and they are easy to buy from but don't always show all of the options you might like.

I also use the Bahn.de website that Laurel mentioned for checking rail schedules throughout Europe. However, they only sell tickets for trains originating in Germany (with some exceptions). For more specific information and prices, the websites of the rail networks that actually operate the trains are the best source of information (ie: Trenitalia or Italo in Italy, SNCF in France, SBB in Switzerland, ÖBB in Austria, Renfe in Spain, etc.).

Depending on which countries you're travelling in, you could also use a website such as www.trainline.com as they display schedules and sell tickets for a number of rail networks in Europe, including those in France, Italy, Germany, Spain and others. In order to buy tickets on Trainline, you'll first have to register on the site and provide payment details. After that, the process is very easy. In some cases they charge a small service fee, but I don't find that to be a problem.

Also Omio gives you good information and additional travel options, e.g. buses. They have most providers listed but not all. Large and established German start-up - booking is fo the same price like on platforms such as www.bahn.de.

Oddly, Man in Seat 61 gives RailEurope UK as the first place to look for train fares in the UK.

https://www.seat61.com/UK-train-travel.htm#Train%20times%20&%20fares

For the rest of Europe, he lists country by country, varying between the national sites and Rail Europe:

https://www.seat61.com/Europe-train-travel.htm#European%20fares

I see for Italy he mentions ItaliaRail, which may explain why newbies bring it up. No mention of Italo Treno, the "other" company running high-speed trains in Italy.

One of the reasons that DB is the best site for train schedules may be because it's not selling most tickets. It collects and shows all schedules that have been published by Europe's various national railways (but skips a few private lines and also Ireland). Our rail info pages provide multiple links, including from https://www.ricksteves.com/travel-tips/transportation/trains/online-schedules.

Web sites that sell tickets rarely show timings for things that they can't sell - whether that's because it's too early, or because certain categories of train (e.g. some unreserved regional trains) are not sold online but are easy to buy in stations, or some countries (mostly central to eastern Europe) don't yet handle international tickets online.

Even if they sell cross-border tickets, national web sites normally can't sell a train segment (or connection) that's wholly within another country. Some third-party agent sites represent multiple countries for a more one-stop shopping experience, if that's important to you. Their access to certain categories of ticket is controlled by their contracts with each individual railway, so they also can't sell everything - nobody does.

I use the rome2rio website for my travel plans as they include bus and ferry options as well as trains. I have just planned a five-week Scandinavia trip using their site and found it great and the options easy to show how to connect say a bus and a train. The site also gives direct links to national railways which are generally the cheapest option and most have great discounts (up to 50%) if you book 3-4 months ahead of time. We have done several 5 week trips travelling exclusively by train and have found booking early and directly (not through third party websites) is cheaper than a rail pass.