CHEAP AGRICULTURAL RAILWAYS. To the Editor. Sir,- Being an engineer with experience in light railway construction in Egypt, India, and the Argentine, I have naturally been very interested in the light agricultural railway discussion which has recently appeared in the columns of your esteemed paper. In talking about light railways, many people at once jump at the conclusion that a light railway means a narrow gauge line, and a vision of a break of gauge at once obscures their faculties, and they impediately denounce the whole thing. This is not the case. Irrespective of gauge, the question of weight of rail is a most important one. The Government has recently called for tenders for the supply of 58lb. and 45lb. rails respectively. If it be the intention to use either of this weight of rail, the Govern- ment is exceeding the weight necessary, and, consequently, con- siderably raising the initial cost of construction per mile without deriv- ing any material advantage in main tenance. There can be no doubt in the mind of anyone who has had experience in light railway construction, that a good, sound, light agricultural railway can be laid in this State for £1,000 per mile. But in doing this, the question of weight of rails is very important. Now, a 35lb. rail is absolutely ample for these proposed light railways, and anything above this is superfluous. As an example, I quote the Argentina railways as follows - Gauge, 3.28ft.: weight of rails per yard in lbs., 32 : sleepers scantling, in inches, 8 x 4 : length, in feet. 6.50; steepest gradient, 1 in 80 ; radius of sharpest curve, in chains, 6.00; width of formation, in feet, 11.50 ; engines, weight on driving wheels, 20 tons; maximum weight per axle, 10 tons; truck load, 5 tons per axle. This light railway- is carrying much more traffic per day, than the proposed light agricultural railway of this State would, possibly for the next ten years, and absolutely at the minimum rate of maintenance, and this with a 32lb. rail. Again, there is the Steepbridge light railway, Derbyshire, England; owned by the Steepbridge Coal and Iron Company. This is a 3ft. 6in. gauge, 35lb. rail. 6-ton axle engine, 4-ton axle trucks, having a daily traffic of 1,500 tons; which his been carried on for years. The proper proportioning of the weight of railway to the traffic to be carried is of the utmost importance to the people of this State. It is admittedly a difficult matter to decide in any new country, the style and class of railway to lay down in a certain district for the traffic that is likely to come upon it. We find many lines in our colonies in a chronic state of bank- ruptcy because the works and rolling stock are out of proportion to the traffic, whereas had the railway been justly proportioned to the traffic to be carried, it would have earned a fair dividend. A light railway first constructed in the district with our stan- dard gauge, but with a weight of rail that will economically carry the traffic that is likely to pass over it for the first ten years would be earning a dividend on its small capital during the greater part of the time, if not the whole, and when the district had become properly developed by its means, the time would be ripe for replacing it with the heavier rail. By the very fact of having the light railway run- ning through a district, the heavier rails can be laid down at a cheaper cost afterwards than if it had been so constructed in the first place. And were the work properly organised, no hindrance to traffic need take place. By following this method of railway construction in the development of poor districts, the country would possess railways which were always paying their interest on capital, and no burden would be placed on the finances of the country. I have sufficient data in my possession to show that a sound and good light railway can be satisfactorily built in this State for £1,000 per mile. Thus, a light railway and a not a wood-cutting tramway, a 3ft. 6in. gauge, 35lb. rail, and truck axle load of 5 tons would he much nearer the proportion of traffic than either a 58lb. or a 45lb. rail.- Yours. etc. HUBERT J. DAVIS. M.E. Adelaide-terrace. Perth. March 13.