THE RAILWAYS (SAFETY MANAGEMENT) REGULATIONS (NORTHERN IRELAND) 2006

For each of the risk categories to which the MWA is applied for carrying out in each year Y (starting from Y = 2010), the assessment steps described in paragraphs 9 to 12, the following phases must be applied for calculating the MWAY

• (a) calculation of the annual observations OBSi returned by the corresponding indicators in paragraph 14 after providing as input the relevant data for the relevant years;the index i takes the values as defined in the formula in sub paragraph (e);

• (b) calculation of the 5-year average (AV) of annual observation OBSi;

• (c) calculation of the absolute value of the difference ABSDIFFi between each annual observation OBSi and the AV. If ABSDIFFi < * 0.01 AV, the ABSDIFFi is attributed a constant value equal to 0.01 AV*;

• (d) calculation of the weight Wi by taking the inverse of ABSDIFFi;

• (e) calculation of the MWAY as follows—

$M W A Y Y = ∑ i = x N W i × O B S i ∑ i = x N W i$

where i is a natural number and x = Y – 6; N = Y – 2.

Measurement units for NRVs and CSTs

14

The following table sets out the measurement units for NRVs and CSTs.

Decision flowchart

15

The flowchart referred to in paragraph 8 is as follows—

Values for NRVs

16

The following table sets out the values of the NRVs for the purposes of this Schedule.

Values for CSTs

17

The following table sets out the values for the CSTs.