Hello Christer Löfving, Strategist at Trafikverket's Unit for Strategic Development!

We've come quite a long way with regard to the major strategic choices, such as deciding the speeds that we'll design the lines for, the voltage to be used, how we're going to construct the lines and the type of signal systems. On the other hand, there are still a great number of detailed technical considerations to be investigated before the construction of a Swedish high-speed train network can begin.

Sweden has chosen to plan for high-speed trains that could reach speeds of up to 320 km/h. Why 320 km/h?

It's a choice based on a number of factors, the most important being benefit to society. Shorter travel times, such as two hours between Göteborg and Stockholm, have major socioeconomic advantages. At the same time, 320 km/h works well in conjunction with the regional train system. What's more, trains have been driven at this speed elsewhere in the world, which means that there are tried and tested solutions and broad experience to draw upon.

What does it mean then to drive trains at 320 km/h, compared with current speeds of around 200 km/h?

The major difference for travellers is the drastically reduced travel times between our three major cities - and therein also lies the greatest societal benefit. But building lines for high-speed trains also means that new and greater demands are made, for example, in respect of the design of the track, planning routes in the countryside and measures to handle noise and ensure safety.

According to the calculations, 320 km/h is also the optimum choice for reasons of economy. What does that mean?

Quite simply, it is the alternative that is best from a financial point of view. We have looked at everything from investment costs to costs for operation and maintenance. If we had chosen a track designed for 360 km/h with another, less proven form of technology, the costs would have been considerably higher.

Trafikverket has elected to use a 17 2/3 Hz and 16 kV electrical supply system– in other words, the same as is currently in use in Sweden. Further south in Europe, other electrical supply systems are often used. What's the reasoning behind this?

We have weighed the pros and cons against each other and arrived at a decision where there is much to suggest that we should use the same electrical supply system as is currently in use in Sweden. Otherwise we would have had major compatibility problems during the transitionary period and would have been forced to rebuild existing trains and systems. What's more, this is a standard that is approved at EU level and which is used in several of our neighbouring countries, and also in major European countries such as Germany.

What does the prescribed track standard with ballast-free tracks mean?

The method, which is also known as "slab tracks", means that the tracks are fixed in a longitudinal concrete slab instead of in sleepers on macadam. This gives a better track bed, requires less directional adjustment and provides a high level of stability. Ballast-free tracks cost more in the investment phase, but are worth it in the long term since the maintenance costs are lower.

The signal system for the Swedish high-speed lines will be the new European standard ERTMS. What does that mean?

This is the standard in Europe which is to be used in all new railway constructions. It is a system which basically works very well indeed, but there have been some regional differences in Europe that have caused problems. But when building a new line it is the obvious choice.

Safety is another important aspect. What's the reasoning in terms of safety?

There are many safety aspects, and the signal system is one of the most important. But we are also putting fencing alongside the track, bearing in mind how many wild animals there are in Sweden, and in order to reduce the suicide risk.

How is the work progressing right now?

We have developed a technical system standard so far and this will be updated continuously as the work progresses. And so far we're just starting work that is going to be in progress for a long time.