I traveled to 4 European countries via train, and I made 3 major mistakes along the way

• I traveled to Switzerland, Germany, Austria, and Italy on Europe's extensive high-speed railway.
• I brought along a 40-pound suitcase, which turned out to be a big mistake.

The European Union has more than 7,000 miles of high-speed rail, connecting dozens of cities around the continent.

In early February, I went on a two-week trip to Europe, on a mission to travel to six countries — including four of them by train. My train journey began in Zurich and ended in Rome, making three-day stops in Freiburg im Breisgau, Germany; Innsbruck, Austria; and Venice.

I didn't have much experience riding trains. Previously, I had only traveled on a 13-hour sleeper train across Thailand. Half a year later, I tried out the shiny new Laos-China Railway to travel to the outskirts of the Laotian capital, Vientiane.

Before the trip, I did as much research as I could. Following other travelers' advice, I made sure to have enough time to make my connecting trips and pack food with me. I also booked on the official websites to make sure my tickets were legitimate.

My journey across Europe turned out to be the trip of a lifetime, with stunning views of the Alps and countryside, but traveling was far from easy. Here are three major mistakes I made along the way, and what you can do to avoid them.

1. I had an overly packed itinerary.

The most challenging parts of my trip were the cancelations and delays, as there were strikes among train drivers in Germany.

I was booked for a two-hour direct train from Zurich to Freiburg im Breisgau on the rail route ICE74, but the stops in Germany were canceled on the day of my trip.

I ended up getting a last-minute replacement ticket from the Swiss national railway company SBB's office, but it required two transfers and only a few minutes to catch the train in between.

Next time, I'll plan a flexible schedule in case of any unexpected changes to my itinerary. It also helps to constantly check the official train apps in case of any cancelations and strikes so you can get rerouted as soon as possible.

2. I brought a massive suitcase.

I'm usually a light packer, bringing only a carry-on bag when traveling around Southeast Asia. But with a low tolerance to the cold winters of central Europe, I packed various heavy coats — and it turned out to be a big mistake.

I had to lug my suitcase, which weighed around 40 pounds, on and off the trains, up and down the stairs at train stations, and drag it across uneven cobblestone streets. I also had a small travel bag filled to the brim with souvenirs, making my shoulder feel sore and lopsided.

In hindsight, I would have been more comfortable packing my belongings in a lightweight travel backpack and a small carry-on suitcase instead of one giant bag.

3. I didn't pre-book my seats for all my train rides.

While some train rides — like the one from Venice to Rome on the Italian train company Trenitalia — were empty, others were packed. Many European train routes have multiple stops, and passengers simply get on and off the train. Seats are subject to availability, and the only way you can secure a seat is by making a reservation.

I experienced a mad rush for seats on a train from Buchs, Switzerland, to Budapest. At boarding, hundreds of passengers scrambled for a seat, while I struggled to hoist my massive bag up the train.

Thankfully, I still managed to get a seat. Some people weren't so fortunate and had to stand.

In the future, I'll pay a few extra euros to make sure my seat is guaranteed.