The point is, a rail system should be able to benefit from economies of scale when compared to a person using a private car to commute.
Ironically this is one aspect of rail transport operation which has been hampered by rail privatisation, and in the decade preceding it due to geographical and functional sectorisation (in preparation of privatisation).
Prior to being split into independent business units, resources such as rolling stock, motive power, staff, buildings/maintenance depots/crew facilities could be shared universally across the different areas of railway operations ; passenger and freight operation etc.
We now have a situation where passenger operations are split by different functional and geographical specialisations, each requiring it's own dedicated fleet of rolling stock, staff, and maintenance facilities.
Freight is an entirely different ball game and is run on a completely private basis, with numerous freight operating companies in existence, each with their own staff, facilities, locos and rolling stock.
The combination of the above has resulted in a number of issues ;
- Lack of flexibility to cater for increased/seasonal traffic flows
- Lack of interoperability between rolling stock
- Reduced ability to change power source when travelling over electrified/non electrified lines
- Increased costs due to duplication of resources and facilities across each Train Operating company
Prior to sectorisation/privatisation, it was common practice for locomotives to be used universally across passenger and freight operations, rolling stock was interoperable, and it was possible to source spare motive power and rolling stock at short notice.
It was also common practice to swap diesel locos for electrics when travelling over electric lines and vice-versa. It was also in many cases possible to transport mail/parcel/newspaper traffic via rail by coupling an appropriate vehicle to the end of a passenger train. Due to the divisive nature of the railway system this is no longer possible, and it is not financially viable to run dedicated trains to transport traffic of this nature.
The above no longer takes place. We have reduced cohesiveness, resiliency and economy of scale across the network. Different types of rolling stock lack compatibility and interoperability, and in many cases it is difficult to increase/decrease train lengths at short notice.
Diesel hauled trains travel for many miles over electrified lines due to it not being cost effective for smaller entities to make provisions for mid journey traction changes. Diesel trains (especially freight) are slower than electric trains, particularly with regard to acceleration etc.
Although the privatised rail network costs significantly more to run (even accounting for inflation) than it did as a nationalised entity, there have been improvements. The average age of rolling stock has reduced significantly, with reliability and customer satisfaction increasing commensurately.
It would be interesting to see what a properly run nationalised railway system could achieve with the level of funding received by all the privatised entities currently in operation.