CONTINUOUS RAILWAY BRAKES. 179 



a front and rear brake-van wero usually attachod to tho 

 train, by which the risk of a part of tho train bein"- loft 

 without braking power, in tho caso of accidental splitting 

 of tho train, was quite avoided, in addition to which tho 

 power of another man was gained. This brake is still in 

 use on a few branch lines, among others, the Cheddar 

 Valley lino. 



Clark's Chain Brake. 



This is an example of a brake belonging to Class II. 



A friction-roller is carried on the last axle of tho brake 

 van, which servos, by frictional contact when set up, to 

 revolve two friction drums carried in swing links, one on 

 each side of the van axle carrying the friction roller. 

 ^ Tho shafts of these two friction drums carry barrels, on 

 to which the chain used for putting on tho brakes is wound. 



This chain passes from the "winding barrel" over a 

 pulley, carried in a swing frame, then underneath another 

 gnide pulley, carried at the extremity of tho horizontal 

 arm of a boll-crank lever, to the end of the vertical arm of 

 which the inclined thrust rods which work the levers 

 carrying the brake blocks aro attachod ; from tho " guide 

 pulley " just mentioned the chain again passes over another 

 guide pulley, hung in a swing frame like the first, and from 

 thence the chain passes on to the next carriage. Tho two 

 guide pulleys, and tho pulley on tho horizontal arm of tho 

 boll-crank lover, form, with the chain, an isosceles triangle, 

 with its apex downwards. 



The action of tho brake is easily seen : as tho chain is 

 wound on the barrel, the "pulley" at the end of the bell- 

 crank lever, and the lever with it, is raised ; the vertical 

 arm, moving away from the vertical, actuates the thrust 

 rods, which in their turn actuate tho lovers carrying tho 

 brake blocks. 



