24 
Indian Forest Records. 
[VoL. IX 
(n) Treated ' Kail ’ sleepers. 
Finns excelsa. Untreated ‘ Kail ’ sleepers were laid down as an 
experiment at the same time as the abovemen tioned untreated ‘ Chir ’ 
and also lasted less than 2-| years. The treated ‘ KaU,’ both Powellized 
and impregnated with Earth Oil and Creosote, have given slightly better 
results than ‘ Chir,’ though the difference is hardly commensurable with 
the difference in price of the two timbers. Though a treated ‘ Chir ’ 
sleeper may last about a year less than a treated ‘ Kail,’ the former is 
probably a better financial investment than the latter. The remarks 
made against selecting and laying of ‘ Chir ’ apply with equal force to 
‘ Kail ’ sleepers. 
(m) Treated ‘ In ’ sleepers. 
Dipterocarpus tuberculatus. Experiments were carried out in several 
localities with untreated ‘ In ’ sleepers and their life was found to be from 
4 to 5 years. The Powellized ‘ In ’ sleepers were all laid in the line in 
one locality and that was a very wet one, on the East Bengal State 
Railway. They have been in the line 9J years and are now fast failing 
and will probably last only 10 to 11 years. The ‘ In ’ sleepers treated 
with Earth Oil and Creosote and which have been in the Burma Railways 
for 6 to 7 years are doing well. As regards the durability of well treated 
‘ In ’ sleepers it is only possible to give their life in wet and somewhat 
unfavourable localities, which is from 10 to 11 years, probably in drier 
localities it would be found to be from 12 to 13 years. The experiments 
with ‘ In ’ brought out one point very clearly which applies equally to 
all true Dipterocarps and that is that this class of sleeper almost invari- 
ably goes under the rail seat and round the spike hole. From examin- 
ation of the sleepers it is thought that this deterioration is not so much 
due to rot as that the fibre being very straight laminates by cracking, 
in other words that deterioration is due to mechanical and not physical 
defects. There can be little doubt that the use of bearing plates should 
be insisted on with all classes of Dipterocarps, such as ‘In,’ ‘ Gurjan,’ 
‘ Kanyin ’ and ‘ Hollong ’ and that it is imperative to either bore the 
holes before treatment or if that is not possible to smear the spike holes 
with preservative at the time of boring and laying in the line. 
{iv) Treated ‘ Kanyin ’ sleepers. 
Dipterocarpus alatus. Untreated ‘ Kanyin ’ sleepers last less than 4 
years ; if well treated they will last 9 years or possibly 10 in the drier 
localities. The Powellized ‘ Kanyin ’ laid in continuation of the above- 
mentioned ‘ In’ sleepers have fared not quite so well as the latter, 
[ 2 ^ ] 
