The everyday greater number of trains and the increase of road transportation in the thickly populated Netherlands, particularly in the heavily built-up west region, made it necessary, in the years 1955 to 1960, to carry out the corresponding work so that the grade crossings which had been used until then, could be substituted by rail crossings at different levels, using tunnels and viaducts.
The lack of space and the high level of water made it compulsory to design structures with a minimum depth.
What has been said before, together with the need of avoiding the servicing of rails in tunnels and viaducts for economic reasons and because of the servicing staff safety, brought the Nerlandesew (N.S.) Railways to the decision of developing a rail design with no ballast for steel and concrete structures.
The application of rails with no splices was indeed very important.
After detailed studies in different laboratories, the actual work was started at a small scale, but soon, this system was adopted for more important structures.
The design has the following peculiar features:
a) Possibility of vertical adjustment (10 mm-2 mm).
b) Possibility of horizontal adjustment (11 mm).
c) Double electric insulation.
d) Application of a rubber-corck damper in two layers.
e) Application of a tridimensional elastic DE anchoring rail system.
f) Application of P 5002 Edition polyester adhesive.
Moreover, there is the structure fixed directly to the concrete framework, with no intermediate concrete slabs, which are considered as unnecessary in tunnels and viaducts and which, besides, increase the height of the structure.
This design has been set, also, for all the experimental rails or the ORE-D 87 Committee.
As low railway for the ORE-D 87 trials, the N.S. developed a prefabricated concrete element system, which has the following advantages over the B.R. and D.B. slab systems:
1. As standard elements, low rails can be built on god grounds as well as on poor ones.
2. The access to those areas, very often difficult along the train rails is no longer to essential.
3. The program and speed of construction can be established according to a fixed working schedule.
4. The carrying out of the work can be done in an entirely mechanical way.
5. It is possible to build the system on existing rails.
The concrete elements can be always adjusted in height, direction and inclination in the curves; furthermore, if necessary all of that can be carried out when the rails are being normally used.
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