Composite brake block.

1.0            Railways have been using following composite brake blocks in Diesel locos.

1.1      L type composite brake block conforming to RDSO specification No.MP.0.0100.04 (REV-07) July 2008 in ALCO BG locomotives (WDM2, WDM3A, WDG3A, WDS6).

1.2           K type composite brake blocks conforming to RDSO specification No.MP.0.0100-10 (REV-03) May-2007 in EMD locomotives (WDG4, WDP4).

2.0           L type composite brake block conforming to RDSO specification No.MP.0.01.00.08 (REV-03) May 2007 is being introduced in MG locomotives (YDM4) in NF Railway.

3.0           These brake blocks are inherently superior to Cast Iron brake blocks due to non deterioration of friction coefficient at elevated temperature and reduced wear characteristics. Major benefits are:

3.1          Improved braking force on full speed range.

3.2          Longer service life.

3.3          Improved wheel life

3.4          Reduced brake gear attention due to less brake block change.

4.0    

Following aspects should be kept in mind for exploiting full benefits of composite brake blocks.

4.1          Monitoring of composite brake block life.  Para 2.17 of RDSO specification stipulates service life of 7.5 months for EMD locomotives & at least 5 times life of conventional Brake block for L series of composite Brake block in ALCO locomotives.

4.2          Sheds should paint a unique ID no. & date of fitment on Brake block back plate and record the same in “Brake block fitment cum   performance register”. This is in addition to traceability requirement of brake block manufacturer as per Para 2.5.2 & 4.2(ii) of RDSO specification.

4.3          Whenever, Brake blocks are required to be changed, date of change & cause of replacement should be recorded in brake block register.

5.0      Brake block register format is given in annexure - I. The same should also be computersied in MS Excel for ready calculation of brake block life. 

5.1          Brake block should normally be changed when brake block thickness is reduced to 10 mm including back plate (Para 2.4.1). Premature change of brake block other than uniform wear is cause of concern & should be investigated properly.

5.2          If brake block is prematurely changed due to crack, hot spots, chipping then such brake blocks should be carefully segregated. Warranty claim should be lodged as per Para 3200, 3201, 3202 & 3203 of Stores Code, Vol. I, and as per Para 9 of RDSO specification.

Joint inspection should be arranged. Matter should be reported to RDSO along with failed sample/photograph of failed component & prima facie investigation report for taking corrective action.

5.3          If brake block is to be changed due to biased/uneven wear, then cause of biased/uneven wear should be investigated.

·         If required, Brake head should be changed.

·         4mm washer should be provided to ensure that brake blocks are kept away from root of wheels.

·         Tie rod should be straight having modified 90 degree cross section.

·         Lateral and longitudinal clearance should be measured & kept in limit if required by providing liners of suitable size.

·         Brake gearing should be compulsorily overhauled during M24 & above schedule & worn out items should be replaced.

·         End play of Brake head, Brake hanger should be controlled by replacing worn pins & bushes.

  6.0 These measures will not only ensure higher brake block life but will also lead to improved wheel life (due to reduced wheel turning due to less root wear).

            

Annexure-I

Loco No.

Loco type

Location

Date of fitment

Identification mark/Lot No.

Date removed

Cause of removal

Total KM earned

Total wear

No. of days run

Wear per month

Wear per thousand KM

Any other observation

Condition of Br. Block/Wear

Warranty claimed or not

Remarks ( Photograph taken)