Page:Popular Science Monthly Volume 90.djvu/694

 678

��Popular Science Monthly

��The Corrugated Wood Block for Street Paving

TH E corrugated wood block marks an important advance in the manu- facture of paving materials. One side and one end of each block are corrugated or grooved in the direction parallel to the grain by a spec- ial machine. These grooves immediate- ly adjoin each other. The dividing lines are of almost knife- like sharpness.

The particular advantage of cor-

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��PAVEMENT FILLER

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CORRUGATED CREOSOTE BLOCK

���The corrugations auto- matically provide the space for the filler

��nigated block lies in the fact that the blocks may be laid snugly together, course on course and block on block, without fear of displaced alinement due to expansion from temperature or moisture. In laying the ordinary block the workmen must attempt to provide a space between the courses and between the blocks in the courses.

With this newly invented block the corrugations automatically provide the necessary space for the pavement filler to flow to the bottom of the block, effectually sealing the pavement against moisture. Under certain con- ditions wood block has a tendency to expand. When this con dition exists with corru- gated blocks, the knife-like edges crush or bury them- selves in the adjoining blocks, relieving the pres- sure at once. Each block has its own expansion joint.

��Clearing a Crippled Car from Railroad Tracks

WHEN a car breaks down on a busy road, it is of first importance to clear it out of the way so that traffic may go on undis- turbed. The car itself can be repaired when it reaches the barn, so that the first prob- lem is to get it there as quickly as pos- sible. For this pur- pose, the master me- chanic of a Western traction company has devised a piece of apparatus which can temporarily take the place of a broken axle on a car. The apparatus is merely an auxiliary truck with small railroad wheels rigidly held apart so that they properly fit into the rails. When a car has broken down, an emer- gency car equipped with a set of these trucks is immediately sent out. The crippled car is lifted up by heavy screw- jacks at the end where it has broken down. The auxiliary truck is then run underneath the broken axle, the car wheels are fitted into the frame, and the whole apparatus is strongly fastened to the car by means of heavy chains. The car then runs back to the barn by its own power.

��The workmen drive the courses snugly and place each corrugat- ed block without having to make calculations for expansion

���When the car breaks down, an auxiliary truck with small railroad wheels is run under the broken axle to support it

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