Alexander — Maximum Bending -moments on Short Girders. 37 



plate h in. thick ; these plates are set li in. apart. On the top of the plates is 



the model girder constructed to a span of 42 feet on a scale of 4 feet to an inch. 



Eunniug on top of the girder is the locomotive, with a wheel-base of 



7| in. (to represent 30 feet on the assvimed scale). The girder does not 



terminate at the supports, but overhangs each support by an amount sufficient 

 to prevent any wheel of the locomotive from running off the girder so lono- 

 as the centre of gravity of the locomotive remains between the supports. The 

 object of this is to avoid the change in the character of the bending-moment 



