RAILWAY CONSTRUCTION. 67 



stratification, and also on its position as regards proximity to 

 buildings or residential property. 



Where the rock is loose, or disintegrated, the pieces can 

 generally be readily separated by picks and bars without 

 having to resort to any great extent of blasting. 



The first of the material excavated in the cuttings is generally 

 conveyed in wheelbarrows to form the commencement of the 

 adjoining embankments. When the wheeling distance becomes 

 too far for economical barrow work, ordinary carts or three- 

 wheeled carts, sometimes termed dobbin carts, are brought into 

 operation where the cuttings and embankments are light; but 

 where the earthwork is heavy, both in excavation and filling, 

 a service or temporary road of light rails and sleepers is usually 

 laid down to carry strong tip earth-waggons. For moderate 

 distances these waggons are hauled by horses, but for distances 

 over three-eighths of a mile a small locomotive is more speedy 

 and economical. Fig. 57 shows one form of dobbin cart; the 

 wheels are made with good broad tyres, so as not to sink too 

 deep into the soft ground, and the body being attached to the 

 framework by a pivot or trunnion on each side, can be readily 

 tilted over, and the earth tipped out, by releasing the holding- 

 down catch. Where the ground is soft and wet, or of a very 

 loose sandy nature, the work of hauling these dobbin carts is 

 very heavy on the horses, and in such cases it soon becomes an 

 advantage to lay down a service road of rails and sleepers. This 

 service road is formed of light rails manufactured for the purpose, 

 or old, worn rails no longer fit for main-line work, spiked down 

 on to rough transverse wooden sleepers. The end of the 

 embankment in course of formation, and where the earth is 

 being tipped, is termed the tip head. Two or more roads are 

 required at the tip head to form the embankment to its full 

 width. Fig. 58 gives a sketch plan of a service road near the 

 tip head. The width is shown as for a double line. The 

 earth- waggons are hauled along the line from the excavation, 

 and brought to a stand at the point A. If a locomotive has 

 drawn the waggons, it is then detached, moved forward, and 

 shunted back into the siding B C. A horse accustomed to 

 tipping then takes one full waggon at a time over one or other 

 of the two turn-outs, DEF or DGH, to the tip head, sufficient 

 impetus being given to the waggon to run the front wheels off 

 the ends of rails on to cross-sleepers laid close, with a steep rise, 



