This is an antique or vintage nickel plated brass railroad luggage, hat or towel rack shelf.
I can’t be certain, but this piece feels very early to me and it may date sometime from the early 20th century, circa 1920s or 1930s. Please use your judgment.
The overall shelf measures 21 inches wide x 6 1/4 inches high x 6 inches deep (53.3 cm, 15.9 cm, 15.2 cm). The usable part of the shelf measures 19 3/4 inches wide (50.1 cm).
Most of these that I see are made of solid brass. This one however is nickel plated.
The bracket on the left side curves outward a touch and the one on the right side inward a touch. There is scattered green/blue tarnishing to the surface. The entire piece has a great old world patina to it.
It is a very solid and sturdy piece.
It weighs 2 pounds 13 1/2 ounces (1.292 kg).