112 REPORT—1849., 
iron rails are rolled, I would suggest that they should be subjected prior to 
use to an uniform course of hammer hardening all over the top-surface and 
sides of top flange of the rail. The effect of this would be two-fold ; the rail 
will be stiffened without any material reduction in ultimate strength ; its sur- 
face will be hardened and polished, and hence best calculated to resist corro- 
sion and abrasion ; and lastly, the direction of the principal axes of the erystals 
of the iron, or of its “fibre,” will for a small depth be changed and brought 
perpendicular to the surface of the rail, by which the tendency to lamination 
by rolling traffic will be greatly reduced. It will occur to any practical 
engineer that machinery may be constructed with perfect facility by which 
this hammer-hardening may be performed with rapidity and perfect smooth- 
ness and uniformity, the bar being slowly advanced, end on, under small 
hammers with suitably formed faces, driven rapidly by power. The total cost 
of the operation would amount to but a trifle on a ton of rails. 
Secondly. I wouldsuggest that allrailway bars, before being laid down, should, 
after having been gauged and straightened, &c., be heated to about 400° Fahr. 
(but not higher, for fear of injuring the effect of the hammer-hardening), 
and then coated with boiled coal-tar; this I have proved in the preceding 
experiments to last for more than four years as a coating perfectly impervious 
to corrosive action while constantly exposed to traffic. The outlay for this 
would be very small; and if its value were no more than that after the lapse 
of eight or more years, when a set of rails had to be replaced in consequence 
of wear, the whole of the iron, which would have otherwise been dissipated 
in rust, would be returned to the furnace to be remade, the outlay would 
be wellbestowed. 
I would respectfully commend these suggestions to my professional brethren 
as worthy of trial, and have now fulfilled, so far as I have been able, the 
commands of the British Association, as to the corrosion and wear of rails. 

