Warnings in a respected railway publication that an enhanced Thameslink timetable from 2018 is unworkable have generated more concerns about the addition of rail freight trains on the same tracks.

Modern Railways, the official journal of the Railway Study Association, has reported that senior industry experts believe that the enhanced Thameslink timetable, due to introduce more peak time trains from 2018, cannot work in its present form.

Thameslink proposes 20 trains per hour in the peak periods from May 2018 rising to 24 trains per hour in December of next year.

But Eric Roberts, local rail expert and spokesman for St Albans Civic Society on the proposed Strategic Rail Freight Interchange (SRFI) planned for the former Radlett Airfield, believes that if the concerns voiced by Modern Railways about improved commuter routes proves correct, there will be no room for freightliners accessing the new depot.

He has voiced his fears to local MPs Anne Main and Oliver Dowden, both of whom have been pursuing Network Rail over what they see as the company’s failure to explain how freight and passenger services can operate in harmony if the SRFI is built.

Mr Roberts said that operating 24 trains an hour would amount to one every two and half minutes and, with increasing demand from Intercity services, would mean Thameslink trains being switched to slow lanes.

He warned: “It does look likely that ‘St Albans - 20 minutes from London’ on a good day will have to be stretched out to around 25 minutes and more for the so-called fast trains.

“Our commuters are in for a shock - higher fares, slower train.”

In the midst of all that, he questions how Network Rail intends to fit freightliners going in and out of the SRFI.

An entirely night-time operation would hit infrastructure maintenance opportunities so would affect the daytime timetable, he pointed out, and the planning application for the SRFI from Helioslough had not specified an entirely covered night operation - which was recognised in the appeal inspector’s decision.

Warning that time was running out, Mr Roberts said: “Some service questions need to be asked of Network Rail’s timetable plans and how it will enable our passenger train operating companies to deliver an efficient, punctual and reliable timetable to passengers/customers.”

In a recent letter to Mrs Main, MP for St Albans, Network Rail’s MD with responsibility for freight and passenger operators, Paul McMahon, said that the company had been working closely with Helioslough this year to evaluate in detail the pathing of trains entering and existing the proposed SRFI.

The MP is due to meet with Network Rail once their SRFI plans are completed.