27 Eindhoven and Breda Prinsenbeek, removing poor ground cables

27.1 Eindhoven

At Eindhoven station, the old lampposts outside the canopy were replaced. The old lampposts were spaced according to a 16-metre grid. The existing cables could be reused as per request. However, on the open central platform on the south side, the insulation value of the power cables turned out to fail NEN3140 (management standard) during the zero measurement.

NEN3140 prescribes that the resistance of the cable in the event of a short circuit must not be too high and that the insulation resistance between the conductors is sufficient. In old cables servicing platforms with long cable routes, the circuit resistance may increase and the insulation resistance decrease rapidly. If the circuit resistance is too high, the fuse will not trip when the last lamppost is energised (short circuit). If insulation resistance is too low, a short circuit may occur in the cable. The NEN1010 new construction standard is even a bit stricter than the management standard, so the new lampposts with old cables would certainly not comply with that. That is why the old cables in Eindhoven were replaced after all. They turned out to be lead-sheathed cables from 1950.

Replacing ground cables is expensive (about €100,000 per stop with 2 side platforms), as the platform has to be dug open (often during a nighttime out-of-service period). Opening up the south side of the two central platforms at Eindhoven station costed around EUR 90,000. Luckily, this could be done without decommissioning due to the width of the platform and the low number of passengers it services. Because there were many side branches with old pole rail connections to the central cable trench though, more digging was required than the trench alone.

27.2 Breda Prinsenbeek

At Breda Prinsenbeek station, the installation was also found non-compliant with NEN3140 after completion. This project involved reusing poles and cables from 1988 and replacing fixtures only. Old NEN3140 reports show that part of the installation had been inadequate prior to the LED replacement as well. Such failures are often located in the open terminal strips or cables in the lampposts. This type of failure tends to be resolved by replacing the open terminal strips with closed, water-resistant lamppost boxes and new cables in the poles. To get the station up to par, it was decided, in consultation with station manager, to remedy the failure and replace part of the cables. To avoid replacing good cables, the failure was localised first. The switch board is located on side platform 1. Side platform 2 is powered via a track crossing. We then had the NS in-house installer:

1. disconnect the track crossing.

2. measure the platforms separately, the failure revealed itself in platform 2.

3. Next, disconnect the last post and measure whether the fault was resolved.

4. When the fault remained, the disconnected the secondlast post.

5. Eventually, the cable between the final 5 posts on platform 2 was found to be faulty.

6. This piece of ground cabling (4 x 16m = 64m) was replaced.

7. opening up 2 side platforms and renewing the cables costs around € 100,000.

9. In this case, the problem was solved for just € 18,000.

Tips and conclusions:

– It pays to search for NEN3140 or NEN1010 errors (rather than replacing everything in one go).

For example, ground cables from 1980 are often suitable for reuse (leave them in).

However, always replace cables from 1950 (tend to have a lead jacket).