4.85
20.0 | 3.20
30.0 | 2.63
50.0 | 2.24
100.0 | 1.97

Fig. 36 gives the loads per axle and the distribution of loads in some
exceptionally heavy modern British locomotives.

[Illustration: Express Passenger Engine, G.N. Ry.]

[Illustration: Goods Engine, L. & Y. Ry.]

[Illustration: Passenger Engine, Cal. Ry.
FIG. 36.]

[v.04 p.0548] In Austria the official regulations require that railway
bridges shall be designed for at least the following live loads per foot
run and per track:--

| Span. | Live Load in Tons. |
| - - - - - - - -|- - - - - - - - - - - - - - - -|
|Metres. | Ft. | Per metre run. | Per ft. run. |
| | | | |
| 1 | 3.3 | 20 | 6.1 |
| 2 | 6.6 | 15 | 4.6 |
| 5 | 16.4 | 10 | 3.1 |
| 20 | 65.6 | 5 | 1.5 |
| 30 | 98.4 | 4 | 1.2 |

It would be simpler and more convenient in designing short bridges if,
instead of assuming an equivalent uniform rolling load, agreement could be
come to as to a typical heavy locomotive which would produce stresses as
great as any existing locomotive on each class of railway. Bridges would
then be designed for these selected loads, and the process would be safer
in dealing with flooring girders and shearing forces than the assumption of
a uniform load.

Some American locomotives are very heavy. Thus a consolidation engine may
weigh 126 tons with a length over buffers of 57 ft., corresponding to an
average load of 2.55 tons per ft. run. Also long ore wagons are used which
weigh loaded two tons per ft. run. J.A.L. Waddell (_De Pontibus_, New York,
1898) proposes to arrange railways in seven classes, according to the live
loads which may be expected from the character of their traffic, and to
construct bridges in accordance with this classification. For the lightest
class, he takes a locomotive and tender of 93.5 tons, 52 ft. between
buffers (average load 1.8 tons per ft. run), and for the heaviest a
locomotive and tender weighing 144.5 tons, 52 ft. between buffers (average
load 2.77 tons per ft. run). Wagons he assumes to weigh for the lightest
class 1.3 tons per ft. run and for the heaviest 1.9 tons. He takes as the
live load for a bridge two such engines, followe