Script to mask areas

[Will]

Hello all,

I have a specific request and I really don't know if it's possible to realise that   

I make surveys of railroad tracks by plane (over 3500 kilometers and more) with a Phase One XF IQ4 150 MP sensor. Photos are heavy and the process too...

I was wondering if it will be possible to make a Python script to create an automatic masking around these railroads and their ballast on each photos (maybe on a range of RGB codes of the rails) ?

If someone had or has had any experience or an idea of processing in this type of survey, I will appreciate any help :-)

Thank you
William