I, too, have trawled the internet, but couldn't find a copy of the full Benson report.
The nearest I could find is the website of the Irish Railway Record Society, at
https://irrs.ie/library/ , but I suspect you'd have to pay for a copy.
Maybe. Next time I'm in Dublin on a Tuesday evening ...
The Historic Railway Law Library has over 1,000 volumes including Acts of Parliament, Orders and Instruments, Royal Commissions, Reports, Text Books, Studies, Papers, Accident Reports and Board of Trade Papers. This collection is housed in the Balfour Browne Room which is also home to our exhibition of railway memorabilia. Visitors and researchers are welcome visit the library on Tuesday evenings.
In fact I wish I had known about this prior to 2018 because I spend an awful lot of time around the Dublin area for work and evenings were - well, the library would have been more exciting.