1840.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



401 



DIRCKS' PATENT IMPROVED METALLIC RAILWAY WHEEL WITH WOOD-FACED TYRE. 



ri^.-. 1. 



FiK. 2. 



Fig. 3. 



I'nw i/lilllllNiiiiil limmi"'^ 



Fig. 5. 



Description. 



the view Ijciiig a front elevation. 



Fig. 1, represents the wheel, ha'f in sedicn, as at A, and half complete, as at B ; 



Kig. 2. edge elevation, in section. , i i • 



Fig. 3. showing the channelled tyre aJcwith the wood inserted at rf, fastened l.y tl.e pin or rivet ee. 



Fig. 4. represents one of the wooden blocks in perspective, perforated with two holes,^, lor receiving the pins or rivets. 



Fig. 5, cross section of arm of w heel. 



Read by Mr. Henry Dircks, before the Mechanical Section of the 

 Brilissh dissociation, at Glasgow, Stpt. 10, 1840. Jliid also before 

 the Polytechnic Society at Liverpool, Oct. 8, 1S40. 



As an introduction to the observations immediately relating to the 

 improved wheel which is the subject of the present communication, a 

 few preliminary observations may serve to make its nature and ad- 

 vantages more generally understood. 



Wooden wheels were originally in common use on railways; these 

 were afterwards superseded by the extensive use of cast-iron wheels; 

 and both of 4hese descriptions of wheels were much improved by 

 manufacturing them with wrought iron tyres. Modifications of these 

 vvheels are still in use on the Liverpool and Manchester Railway, the 

 wooden wheels having the nave of cast iron, and the spokes and rim 

 of wood, the tyre being of wrought iron. On the London and Bir- 

 mingham Railway, cast iron wheels are extensively used. On the 

 continent of Europe, and in America, cast iron wheels are seemingly 

 employed by preference ; and are no doubt quite as safe for travelling, 

 where great speed is not practised. 



In England, a decided preference is given to wrought iron wheels, 

 in which this metal is used throughout, with the exception of the boss 

 being cast around the ends of the spokes. The latest improvement 

 on these has been the making of the entire wheel, including the boss, 

 of wrought iron. 



The wheels now in general use derive their chief novelty from the 

 construction and placement of the spokes, with a view to obtain elas- 

 ticity, strength, and durability. One variety which does not come 

 under this denomination, is the plate wheel, supposed on its intro- 

 duction to possess some peculiar advantage in overcoming a supposed 

 resistance of the atmosphere. Except, however, in relation to vari- 

 ations in size, the present wheels are little more than varieties in 



pattern. The common diameter of carriage and waggon wheels is 

 three feet, and the largest driving-wheels for locomotives are those 

 employed on the Great Western Railway, being six to seven feet in 

 diameter, — thougli at one time they were made as la.ige as ten feet. 



The action of an iron wheel on an iron rail, though derived firom a 

 rolling motion, can only be compared to a series of blows, and the 

 rebound occasioned by iron striking iron is well known to be con- 

 siderably greater than is produced by striking wood on iron. To this 

 simple fact we may trace the tremulous motion occasioned by iron 

 wheels on an iron railroail ; and when, by any trifling accident, as an 

 inequality from the rising of one end of a rail, or sometimes even from 

 small flinty pebbles getting on the rail, the rebound is not more fearful 

 than dangerous. The tremulous motion of the rail just adverted to 

 renders it necessary in most cases to lay the rails on wooden sleepers. 

 As an illustration of what is meant, it may be mentioned that on the 

 Dublin and Kingstown Railway the rails were originally laid on granite 

 sleepers, but the tremor was so great as to loosen the rails, and oc- 

 casion serious fears from the consequent damage sustained by engines 

 and carriages passing along the line. It was, therefore, ultimately 

 agreed to take up the granite and lay down longitudinal wooden 

 sleepers, a work of considerable labour and expense. In some cases 

 the nature of the soil or sub-soil may allow the use of stone blocks; 

 and where they can be applied with safety, they are preferred, for the 

 reason that a road laid on stone blocks can be kept up at a lower rate 

 than one laid on woodtn sleepers ; and, as has been endeavoured to be 

 clearly shown, the only reason for laying the stone aside, arises from 

 the tremor imparted to the rail by iron wheels as at present used. 

 Brees, in his Railway Practice (1839), gives, in a copy of an estimate 

 for work on the "North Union Railway," the following particulars, at 

 page 142: — 



3 I 



