112 AMERICAN INSTITUTE. 



sion and contraction of the bars by change of temperature is 

 provided for. One rail cannot be raised above or he depressed 

 below another; the track must present a smooth, continuous and 

 even surface. In proof of this, persons interested are requested 

 to examine the track before referred to. To show the economical 

 value and utility of the improvement, the following estimate is 

 presented for consideration, by the exhibiter. 



The heaviest rail, now in use on most railroads, weighs about 

 75 lbs. per yard, or 132 tons per mile. The cost, at $80 per ton, 

 is $10,560 per mile. Rails last, on an average, about eight years, 

 at the expiration of which the iron is worth say one-half its ori- 

 ginal cost, or $40 per ton. Thus the annual depreciation is |660 

 per mile. It is a well authenticated fact, that the iron gives way 

 first and principally at the joints, on account of the inequalities 

 presented to the wheel. It is not an improbable supposition to 

 say, that by means of the Lock Joint improvement, the rail will 

 wear two years longer, making a saving of$l, 320 per mile, or for 

 460 miles of track, $303,600 per annum for two years. 



Again, there are 600 chairs to the mile, weighing about 25 lbs. 

 each. By dispensing with these, the sum of $450 per mile will 

 be saved, or on 4G0 miles of road, $207,000. Add to this six 

 spikes to each chair, valued at $101.25 per mile, or $46,576 for 

 460 miles of track. These chairs and spikes are renewed about 

 once in four years. 



There is still the diflerence in time required to lay the two 

 kinds of track, which exhibits a difference in favor of the improve- 

 ment of $12,000 for 460 miles of track. 



The cost of keeping track in repairs is estimated at $1.25 per 

 day per mile, or $179,975 per annum for 460 miles. Of this sum, 

 at least 25 per cent may be saved, amounting to $44,993 per annum. 



The estimate for cutting and fitting the joint upon the old rail, 

 after it is prepared, is 40 cents per joint. The new rail can be 

 fitted where it is .manufactured more advantageously and at a 

 cheaper rate, making it preferable in point of economy over the 

 present method. [^ bronze medal awarded. 



