New Delhi: Indian Railway Employees Federation (IREF) has written to the railways demanding an enhancement in the productivity-linked bonus (PLB) that the workers get every year ahead of the festive season. The railways pay PLB, which is equivalent to 78 days’ wages, to all non-gazetted employees (Group C and Group D) as an incentive to increase productivity and ensure safety. The PLB is calculated on the basis of the minimum salary paid to the lowest grade (Group D) employees.