Just a few random thoughts on previous scenarios.
The late 1980's , certainly in London and South East had a nasty fall in patronage (and indeed from property revenue in the days when there was a BR Property Board - which put a good deal of one way income + rental income into the coffers) , with the result that both "city" commuting fell by around 30% up to about 1992 /3 /4 , which resulted in a scrapping programme of older slam door stock and a "sweat the assets" policy on those that survived. Moving stock around in BR days was pretty simple without leasing arrangements etc , as long as the depots could handle the work. Key mixed traffic depots like Stratford were hugely reduced in size.
A broadly 5% cut in services was ordered - which was often done by knocking out first and late evening trains , and slashing Sunday services , - hard to imagine now that Thameslink North was reduced to basically 1 tph on Sunday mornings.
Optional leisure traffic fell off a cliff , despite every effort to nurture it. Station staffing was cut right back in all areas. Investment slowed right down bar critical areas / safety related matters post Clapham in particular.
Overall staff numbers were reduced all over - Area Managers took over increasing geographical areas for example from previous patterns. (such that the AM Waterloo found his terrain now stretched to Dorking ! , Swansea had about a third of Wales. The BRB issued at least twice , special "severance packages" to encourage people to leave at their own volition , rather than force severance through reorganisations. Many experienced managers took the hint and left at the age of around 50 or so , when they could. Challenging times
The Speedlink Network was effectively curtailed , remaining bulk (say non coal) block trains were examined and if there were resource issues, or an inability to increase revenue from the customer - were squeezed out.
So what were the causes of this substantial reduction in staff across all functions ? A mixture of :-
(a) Serious fall in Central London Employment (and elsewhere)
(b) Less high value Inter-City traffic due to general recessions / less optional traffics
(c) Less L+SE leisure traffic in general (though some would say that lurking IRA activities played a part in that following a number of severe incidents in Docklands , and the City , Harrods , Ideal Home + smaller ones in many other areas.
(d) The results of de-industrialisation , run down of the steel and coal industries etc.......
(e) Reducing cash support for regional passenger services - in both urban , and especially rural areas. Some line closures , but general thinning out.
So , I hope that this (depressing) portrayal of the past has not ruined your Friday.
We are in uncharted waters to use a common term.
My guess is that the awareness and contractual protection of the social passenger railway , the carbon agenda etc will hopefully spare us from the worse.
I can see a marked reluctance to go for "growth" in the short term. At least on the existing operational railway. Be interesting to see how much of the December timetable gets implemented. It will take time to"bounce back" 9/11 knocked the airline business back for about 2 years , Hatfield dented figures for a year or so. These tragedies materially different to a bottoming World economy that we have at the present. After lockdown , despite a yearning to get out and about , significant percentages of optional passengers will be cash strapped due to employment / debt issues. Previously discussed commuting flows may well be reduced due to "WF Home + technology"