I rode in business and first class on Amtrak's NextGen Acela, the fastest train in the US. Here's how they compared.

First, I spent $180 for a three-hour business-class ride from New York City to Washington, DC.

Since the Acela doesn't have coach seating, business class is the standard ticket.

Then, I rode home to New York in first class for $450.

My first-class ticket included a meal, priority boarding, attendant service, and lounge access at the train station.

The differences between these two bookings began when I arrived at each station.

I waited for my business-class train to Washington, DC, on the floor of NYC's Penn Station. The waiting room was full, and it would have cost me $50 to access the Metropolitan Lounge, which is complimentary for first-class passengers.

Since I held a first-class ticket for my ride home from Washington, DC, I had access to the Metropolitan Lounge at Union Station. Other passengers can pay $35 to enter the space.

The lounge was quiet and calm. There were couches, comfy chairs, tables, and colorful works of art on the walls. I especially appreciated the espresso and beverage station, snack bins stocked with a variety of treats — all of which were complimentary — and the clean bathroom.

I boarded earlier for the first-class ride.

After relaxing in the lounge, I waltzed into the priority boarding lane for my first-class ride to New York. There were fewer than a dozen people in front of me.

Unlike when I rode in business class, where I was toward the back of a long line, I had several minutes to get situated on board before the train departed.

Inside the train, the cars were color-coded.

Aboard the Acela train, I quickly caught on that blue meant business class and red meant first class. From the headrests to the bathroom doors, the matching colors made it easy to tell which car I was in.

Another key difference was the layout. There were two rows of seats on either side of the aisle in business class, while first class had a single row of seats on one side of the aisle.

The seats had all the same amenities, but my first-class one was slightly more spacious.

The NextGen Acela seats had smooth lining, soft cushions, and supportive, winged headrests. They also had reading lights, USB ports between seats, and a reclining function.

The only significant difference I noticed was that the first-class seats were larger and had more legroom. I found both to be more comfortable than any other Amtrak seat I've booked.

Only the first-class ticket included a meal.

During my business-class ride, I grabbed a bite in the café car, where passengers can purchase grab-and-go meals from a self-service station, as well as snacks, drinks, and quick hot meals prepared by an attendant. I ordered a breakfast sandwich, which I thought tasted pretty decent for a microwaved meal, and brought it back to my seat.

In first class, I received attendant service and had a menu of complimentary meals to choose from.

I selected the chicken dish, which consisted of a charred thigh paired with roasted squash, verde sauce, a hard roll, and a Key-lime pie in a jar.

It was the most delicious and satisfying meal I'd ever had on an Amtrak train.

The bathrooms were identical.

Save for the color of the door, the bathrooms in each class are the same, an Amtrak representative told Business Insider. I was impressed by how clean, spacious, and high-tech they were.

These bathrooms featured automatic doors, lights to indicate when the space was in use, and ample room to stretch. I also appreciated the touch-free faucets, soap dispensers, and hand dryers.

Ultimately, I discovered that the fastest train in America was also the most comfortable.

After my back-to-back three-hour journeys on the Amtrak NextGen Acela train, I expected to be thrilled to get off the rails. But my experiences were so comfortable that I was in no rush to exit. When we pulled into NYC's Penn Station, I let other passengers get off first while I soaked up a few more minutes in my first-class seat.