fishbelly

plural fishbellies

1. The belly of a fish.
2. An early kind of cast iron rail for railways, predating the bullhead rail.

   1 more example

   Original stone Stockton & Darlington Railway sleepers, thought to be 195 years old, have been installed as close as possible to the route's original starting point. They carry replica fishbelly rails, and the project [...] was part of an initiative by the Brusselton Incline Group to mark the start of the five-year countdown to the S&D bicentenary celebrations in 2025.

   2020 October 21, Howard Johnston, “Regional News: Eastern: Shildon”, in Rail, page 24