NATIONALISATION or privatisation - which way will Britain's railways go?

The interminable debate over which model is best for passengers and taxpayers has reared its head again in recent weeks with, on one hand, the election of Jeremy Corbyn as leader of the Labour party, and, days later, the admission by the executive in charge of reviving Network Rail's fortunes that she may recommend a partial or total sell-off of the publicly-owned infrastructure body.

For ordinary passengers, understanding who is responsible for what when it comes to their journey - from rail fares to the punctuality of their morning train, the reliability of the wifi on board or the signalling fault which forces them onto a replacement bus - can be bewildering.

If social media is anything to go by, most blame ScotRail (or whichever other operator's train they are using at the time).

In simple terms: ScotRail is the franchise overseen by Government, Abellio is its current operator, the trains are leased from private rolling stock companies, and the tracks, signalling, overhead cables and some stations - including Glasgow Central and Edinburgh Waverley in Scotland - are owned by public body Network Rail.

Journey cancelled due to signalling fault? Blame Network Rail.

Unhappy at the price of your train ticket? If it's a regulated fare - such as season tickets - direct your ire at the Government.

Unregulated fares, such as off-peak leisure travel, are decided commercially by the train operating companies - Abellio, Virgin, First and so on. Profits are narrow though - according to the Association of Train Operating Companies (Atoc), an average of three pence in every £1 paid by passengers went into the operators' pockets. Meanwhile 73p in every £1 went on staff costs, maintaining the track and trains, and investments in the rail network - all influenced by Government policy - while another 11p covered the cost of leasing the trains from the rolling stock companies.

Trade union RMT recently complained that rolling stock companies were "laughing all the way to the bank" while commuters endured standing room-only journeys on overcrowded carriages.

It is obviously up to the operator to manage its rolling stock as efficiently as possible by allocating trains where demand requires. The furore over the Borders Railway was a good example. A victim of its own success on the one hand, but passengers were rightly frustrated that - after all the fanfare surrounding its launch - managers did not anticipate the demand.

But lurking in the background are the rolling stock companies who earn around £86 million from ScotRail - that is, taxpayers - every year.

If trains were cheaper to lease, maybe there would be more of them to go around?

If Jeremy Corbyn has his way, all rail franchises will be brought back into public hands as they expire. His "people's railway" promises "more efficient services, proper integration and fairer fares".

But if public ownership is the panacea, where does that leave Network Rail? Mired in mounting costs, debts and delays, it was blasted in June this year over its backlog of repairs. In Scotland alone, around half of plain track renewals and signalling upgrades were behind schedule.

Public or private, our railways just need good management.