EN 13231-2-2020 pdf download.Railway applications – Track – Acceptance of works – Part 2: Acceptance of reprofiling rails in plain line,switches, crossings and expansion devices.
see 3.7. Approved instruments do not otter the same accuracy as relerence instruments but are generally adequate for the purpose of demonstrating compliance with the requirements of this document.
NOTE An example of an approved instrument is the type of system used for routine corrugation measurement. Some of the systems used on reprofihing trains fall Into this category.
In accordance with current practice, limits are set on the magnitude of the irregularities that can remain in track after a reprofihing operation. It is recognized, however, that it can be uneconomic to achieve 100 % compliance with these, particularly where isolated rail running surface defects, such as wheel burn, exist prior to reprofiling. Two classes are therefore offered, differentiated by the percentage of the reprofiled track meeting the specified criteria. Where isolated top faults exist, class 2 offers a lower cost option compared to class 1 as it will be achieved with fewer passes. However, a larger number of isolated non-compliant zones will remain in the reprofiled site.
Class 1 also includes limits for very short (10 mm to 30 mm) and very long (300 mm to 1 000 mm) wavelength residual irregularities: these are not included in class 2. Where very short waves need to be removed, in particular for noise reduction, it might also be necessary to specify a criterion for those wavelengths.
For the necessary annual metrological check, see Annex D.
4.2 Measurements required
The longitudinal profIle of the finished reprofiled rail shall be recorded continuously using either a reference instrument or an approved instrument. Where independent verification is required a reference instrument shall be used. All measurements undertaken in order to demonstrate compliance with 4.3 shall be recorded
Due to the complex geometry and short length worked on in switches and crossings and expansion devices manual measurement systems can be used alternatively. The rail containing the frog shall be measured only in “Zone G”, see Figure 1; the opposite rail shall be measured in the total ground length.
Longitudinal profile measurements shall be made within a position of 15 mm laterally on the rail from the reference point A to the gauge corner area, to produce the traced profile.
NOTE It is a known issue that some networks have corrugation on high rail gauge corner. This document does not deal with this issue. IM and contractor can agree on measurement methods and acceptance criterion.
It is recommended that a digital form of the traced profile, the primary profile, be used for subsequent analysis.
If such a system is out of order or not available recording details shall be settled in the contract.
The measurements can be undertaken immediately after work or at the latest within 8 days of reprofiling or before the track has carried 0,3 MGT (Million Gross Tonnes) of traffic.
Measurements are made using either a reference instrument, see 3.8, or an approved instrument, see 3.7. Approved instruments do not after the same accuracy as reference instruments, but are generally adequate for the purpose of demonstrating compliance with the requirements of this document.
Reprofihing can be undertaken for a variety of reasons. Where reproflhing is undertaken purely for the removal of corrugation, there could be less need for the rail to be reprofiled with precision. In other cases, it could be necessary for the reprofiled rail to match closely the ideal profile, represented by the reference rail, see 3.30. A range of classes is therefore included to enable the client to specif’ the level of precision that is appropriate for the site to be reproliled.
NOTE Where reprofiling is undertaken to improve conicity, class Q. see 5.4. is likely to be appropriate.
The match between the reprofiled rail and the profile of the reference rail is determined by aligning the two at two points and measuring maximum difference between them, see Figure 4. For straight track, these points of alignment generally approximate to the rail crown and the gauge point. On the high rail of curves, this method is not applicable if side wear has occurred and an alternative method of alignment is therefore used.
For the necessary annual metrological check, see Annex D.
5.2 Areas in switches and crossings which are limited for reprofiling
The areas where the switchblade touches stock rail (Zone F, see Figure 1) and the frog area (Zone 1-1. see Figure 1) cannot be reprofiled completely. The infrastructure manager can define applicable restrictions.
5.3 Measurements required
The rail’s transverse profile shall be measured using either a reference instrument, see 3.8, or an approved instrument, see 3.7. Where independent verification is required, a reference instrument shall be used whereby measurements of each rail shall be made at an interval of not less than 10 m throughout the reprofihing site. A deviation of 0,1 mm between the reference instrument and approved instrument would be acceptable according to Annex B.
All measurements undertaken in order to demonstrate compliance with 5.4 shall be recorded.
The measurements can be undertaken immediately after work or at the latest within 8 days of reprofIling or before the track has carried 0,3 MGT (Million Gross Tons) of traffic.
NOTE It is best practice for measurements to be made immediately after reprofiling.
After reproilling rails in switches, crossings and expansion devices, additional verifications can be specified by the IM.EN 13231-2-2020 pdf download.