Green Garjan, Dipterocarpus spp. sleepers, which are very difficult to treat, were treated successfully with an oil-borne preservative. Bethel full cell process was followed. Before treatment the sleepers were conditioned by alternate steaming and vacuum to facilitate impregnation. Sleepers thus treated had an average penetration of 4.9 cm (1.95 in) which is higher than that required for outdoor use in Bangladesh.

The necessity of adjusting the temperature as well as the duration of pretreatment in relation to residual moisture content of green Garjan sleepers has been discussed.