It is sometimes claimed that a steel wheelway makes a very durable road. As far as the steel rails are concerned, this is true; but it is not true of the surface adjoining the rails—what ever that surface. It is often assumed that the space adjoining the steel rails is to be paved 1\ it 11 crushed stone. If this is done, vehicles in turning out to pass each other will certainly wear ruts adjoining the rails, as is shown by the ruts worn in the most durable pavements by vehicles turning on and off of street-car rails. Fur ther, it is well known that tracking is one of the most effective causes of the destruction of crushed-stone roads, partly because the stones loosened by the horses' feet are not rolled into place by the wheels; and consequently the horses' feet will be more destruc tive on a macadamized steel wheelway than on an ordinary crushed stone road. It has been estimated (§ 372) that the wear of ordi nary macadamized roads due to the horses' feet is 14 to 3 times as much as that due to the wheels. In consideration of the tendency of the wheels to produce ruts adjacent to the rails, and of the failure of the wheels to roll into place the stones loosened by the horses' feet, it is probable that a steel wheelway will at best add nothing to the durability of the adjoining macadam.
If the space between the rails is paved with a more durable material than macadam, the cost will be unreasonably great. The question of cost will be considered in the next section.
Disadvantages of Steel wheelways. The most serious ob jection to a steel wheelway is that if it does not have a perma nent footway for the horses it is least effective in a muddy time, i. e., when most needed; and if it does have a permanently hard surface between the rails, the cost is unreasonable.
If a steel wheelway is laid in a crushed-stone road, the additional cost will be (1) the cost of the metal, (2) the cost of placing the metal, including the increased cost of compacting the crushed stone, and (3) the increased cost of maintenance.
1. The steel wheel shown in Fig. 67 and 68, page 265, will require about 121 tons of steel for a mile of single track. The cost, delivered, would probably not be less than $40 a ton, in which case the metal for a mile of single track will cost $4,840. In this connection it should not be forgotten that experience with the above described steel wheelway shows that the rails are too light for any considerable traffic.
2. The cost of placing the metal will vary considerably with the design of the track and with the thoroughness with which the stone is compacted around the rails. Only practical experience can determine how much labor will be required to form an even bed for the rails, to bolt together the rails and attach the gage-ties, and to consolidate the stone around the rails and the ties, but it would probably amount to at least $500 per mile. There are 14,000 feet of lumber in a mile of single track like that shown in Fig. 67, which in place will cost at least $25 per thousand feet, or $350 a mile. If concrete is employed, it will cost two or three times as much as the lumber. The total cost of placing the metal will thus be at least $850 a mile of single track.
3. It is impossible accurately to estimate the cost of mainte nance. Only experience can determine the amount of labor re quired to prevent low joints and to fill up the horse paths and the ruts next to the rails. However, it seems reasonable to estimate that these expenses will amount at least to as much as the main tenance of an ordinary crushed-stone road to carry the same traffic; and hence in this comparison such expense may be neglected.
The total cost of the wheelway proper would then be $4,840 + $850 —$5,690 a mile over and above the cost of a crushed-stone road. What are the advantages to be derived from this expendi ture? Only the possibility of a slight decrease in the tractive power. In considering the effect of this decrease, it should be remem bered that it is of value only to fully loaded teams; and, further, that such an advantage would accrue only to such fully loaded teams as haul their load from start to finish upon the steel wheel way or other equally good road. The above cost would then be incurred for a very slight advantage to a very small part of the traffic, and therefore there are few circumstances under which the cost of a steel wheelway would be justifiable.
A single-track wheelway is undesirable, since vehicles must turn out frequently in meeting each other, and since either the slowest team will regulate the speed of the procession or the faster teams must turn out and go around. Turning out is diffi cult on account of the flange on the rail; and, further, the sliding of a wheel against the flange causes the opposite wheel to tear up the macadam surface. A double-track wheelway would only partially remove the above objections; and ordinarily where there is traffic enough to justify a double-track wheelway, a uni versal wheelway, i. e., a first-class pavement, should be built. On the double-track steel wheelway described in § 396, more than half of the vehicles turned out and went around the slow ones.
Another objection to any wheelway is that owing to the comparatively narrow space between the rails, the horses are compelled frequently to step upon the rails, the smooth surface of which interferes with the footing of the horses. This in a con siderable measure neutralizes the advantage of a smooth track for the wheels. Teamsters using the steel wheelway described in § 396 strongly urged this objection, and in addition claimed that the projecting flange injured the frog of the horse's foot.
Still another objection to a wheelway is that the gage of vehicles varies considerably, and consequently either the face of the rail must be very wide—a requirement which adds expense,— or some vehicles can not be accommodated. In almost any large city, wagons are found with gages varying from 4 feet 8 inches to 6 feet.
The conclusion is that trackways are out of date; that they are more expensive and less effective than good macadam roads; and that for a country road where an ordinary macadam surface does not suffice, a first class pavement or a railroad should be built.