You could look at whether there's something to do at the web server level (e.g.
https://httpd.apache.org/docs/2.4/mod/mod_reqtimeout.html) but that might not actually kill the rails process as you suggest.
There might well be something on the rails/rack side that could do this, but nothing immediately comes to mind so would need a bit of research. Do let us know if anything useful arises, and if you make any performance improvements to views that we can pull back in to Alaveteli core.
Best,