18 MATERIALS AND SUPPLIES

2018

2019

RMB’000

Raw materials

160,048

171,532

Reusable rail-line track materials

75,415

58,502

Accessories

59,261

40,224

Retailing consumables

1,493

1,001

296,217

271,259

The costs of materials and supplies consumed by the Group during the year were recognized as "operating expenses" in the amount of RMB1,736,886,000 (2018: RMB1,658,327,000).

As at December 31, 2019, the balance of the provision for writing down the materials and supplies to their net realizable values was approximately RMB17,640,000 (2018: RMB37,820,000). During the year, additional provision of RMB14,242,000 was made, RMB3,449,000 was reversed as the recovery price increased and RMB30,973,000 was written off arising from realization of losses in the disposal of these assets (2018: RMB19,128,000, RMB7,767,000 and RMB2,007,000).