Line scan camera image processing for train photography

Perhaps some of your noise issues are solvable by using a lens with a large aperture?

Photo finish lenses used to be wildly expensive and sometimes one of a kind.

Yeah they have a whopping 300mm f/2.0 lens for photo finish! I have been using various primes including a Samyang 135mm f/2, Voigtländer Apo Lanthar 125mm f/2.5, Voigtländer Nokton 58mm f/1.4, Voigtländer Ultron 35mm f/1.7, Myutron 50mm f/2.6, etc. The problem with a really large aperture is that it's hard to nail focus.