This photo compares the SBB CFF FFS RABe 502 by Bombardier (left) and the RABe 511 by Stadler Rail (right). Both are double-deck trains of similar design, shown here in a standard 2nd-class upper-floor compartment.

Findings:
The windows are actually the same size.
The 502’s tables are 74 cm above the floor, while the 511’s are 68.5 cm.
The front edge of the seats on the 502 is 3 cm higher than on the 511.
Legroom on the 502 is slightly larger.
Backrests on the 502 are 4 cm farther apart than on the 511.
Seat depth: The 502’s seating surface is 3.5 cm shorter than the 511’s, creating an optical illusion of more legroom.
Actual free space between seats: 53 cm on the 502, compared to 42 cm on the 511.

Seating comfort:
Bombardier’s RABe 502: Offers a more comfortable upright sitting position, reducing the tendency to slide down.
Stadler’s RABe 511: The backrest is too curved, making it less comfortable for long periods. Most people do not sit with a hollow back naturally.

Visual impression:
The Bombardier design looks cleaner and less cluttered.

Design Flaws: Trash Cans
Weak point: The plastic hinges on the trash cans under the tables. To empty them, they must be pulled beyond their normal limit, forcing the container to fold down—a potential durability issue.