DECIMAL CLASSIFICATION 
Suspension bridges 
Flexible Rope bridge 
Rigid 
Cables 
Towers or piers 
Anchorage 
Archt bridges 
Wood 
Masonry 
Stone, brick, concrete, reinforced concrete 
Metal: iron and steel 
Hinged arch 
Compound structures 
Structurally compound; e. g. plate girder and suspension, trussed arch 
Movable bridges Drawbridges 
Bascule: counterpoise, folding 
Swing: pivot, swivel, turning 
Lifting 
Whole bridge lifted vertically 
Rolling 
Ploating; see also 624.87 
Aerial and other traveling bridges 
Pontoon bridges: floating, boat or raft 
Roofs 
For other relations see Roofs in Relativ index 
625 Railroad and road engineering 
May be divided by n and oo like 620. For railway operation see 656 
Way and works 
Route 
Reconnaissance, preliminary and locating surveys; center line; grades; 
curvs; switchbacks 
Permanent way Roadbed 
Earthwork: surveys, computation, classification, cuts and fills. Drainage 
Structures: tunnels, culverts, snowsheds 
Class here general works on tunnels; see also mining 622.26 
For bridges and trestles see 624; for transportation bildings see 725.3 
Track: ballast, ties and tieplates, strains 
Including general works covering also rails and their accessories 
Monorail tracks 
Rails and accessories 
Rail braces, rail joints, chairs, track bolts, nut locks, spikes 
Track accessories 
Turnouts, switches, sidings, bumping posts; crossings; signals: turn- 
tables; ashpits, track tanks; cattle gards 
Road maintenance and repair Materials 
Road equipment 
Fences, gates, platforms, track scales, yards, etc. Stations, depots, shops 
etc. considerd as road accessories 
For stations, depots, roundhouses, etc. see 725.3 
For shops see 621.7 
Other topics 
624.5 
.52 
53 
55 
56 
87 
0 
62 
03