66 ANNUAL REPORT 
joints were used in building the walls of the wheel pits. Figures 12 and 
13 show the blocks and the wall respectively. 
It is only during the last decade that railroad companies have been 
developing concrete construction along these lines to any extent. The 
Illinois Central, the New York Central and Hudson River railroad, and 
other large roads are now doing a great deal of concrete work. 
ABUTMENTS. 
In many cases when the old abutments and masonry walls are still 
-in fair condition, but are not heavy enough for the increased weight of 
bridges and rolling stock, or because of added fills, the old masonry has 
been re-enforced by an additional casing of concrete, thus preserving the 
old masonry and adding a large percentage of strength to the structure. 
In other places the old masonry is removed entirely and concrete substi- 
tuted. 
Fig. 14.—Concrete Abutment on the D., S. & U. R. R., Near Dayton, Ohio. 
Some railroad companies have shown timidity in using concrete to 
entirely replace stone for piers and abutments of long span bridges; 
especially for the bridge seats, because of an uncertainty as to the dur- 
ability of concrete under vibrating and impact strains. The New York 
Central and Hudson River railroad limits the use of concrete piers or 
abutments to bridges having spans less than 200 feet long. 
The Dayton, Springfield and Urbana Electric Road has lately con- 
structed two large abutments to carry their ‘road over the tracks of the 
