In response to recent letters and articles concerning train operator Southern, some background information on the new trains including why we need to introduce them might be helpful to readers.

It was agreed that slam-door trains would be removed following the Clapham Rail crash in 1989. It was considered their safety characteristics were insufficient and therefore they had to be replaced. At Southern we are now undertaking the task of replacing our slam-door fleet and bringing the biggest improvement to our network for 40 years.

We are introducing 700 new electric trains in a comparatively short timeframe. At the same time, we need to modernise the depots in which these trains are maintained. Failure to do the latter will prevent us from running a train service. Failure to undertake the former will put us in breach of the law.

A three-year delay in signing the Southern franchise meant we were unable to complete the depot work before introducing the new trains - although we did undertake a lot of work in advance, such as increasing staffing, ordering new trains and starting the depot upgrades. Once the franchise agreement was signed last year, the financial resources were released and we could get on with the job in earnest.

We have always said this network couldn't be transformed overnight and, when we changed our name from South Central to Southern in May, we made it clear that improvements would take two to three years. Our new train introduction is on schedule and should be completed by the latter part of 2005. Overall, our depot work should be completed during 2006. Both are well ahead of the projected timescale.

The new trains and upgraded depots will bring a better service to customers and better working conditions for staff.

The lack of power on the network initially delayed our ability to introduce the new trains as quickly as we would have liked. We have now introduced more than 300 carriages to the network. A total of 400 have been manufactured and the remaining 300 are to be produced. Comments about the trains being in mothballs are inaccurate.

The problems we are experiencing with these new trains are annoying for both passengers and ourselves. We have always acknowledged problems when they occur and are working with the train manufacturer to iron out issues such as incorrect information on trains and faulty doors.

The trains do provide vastly improved information for passengers as well as improved levels of safety and a decent journey for passengers with disabilities.

They are heavier because of the introduction of air conditioning systems, larger toilet facilities and safety systems - all designed to enhance passenger comfort and safety.

Contrary to your report on Monday, thorough testing of trains is undertaken. It is only when the train enters public service that we find how various components withstand the stresses and strains of such work.

The Mark One slam door trains now being withdrawn from service suffered acute reliability problems when they were first introduced. There are many other examples of such teething problems.

While this is irritating for us all, there is no immediate alternative to this process and we are working to remedy these problems as quickly as possible. The GPS system was subjected to extensive testing and trial before it was brought into use.

We do not enjoy the delays any more than our passengers. We assure all readers that we are working flat out to get the new fleet fully into service and identify and rectify malfunctions as quickly as possible.

Diaries and letters to The Argus make for a good read but readers don't get the full story.

Passengers are always welcome to contact us directly by visiting our web site www.southernrailway.com or calling our customer services team on 08451 272920.

-Samantha Hodder, Head of Communications, Southern