THE MEMPHIS BRIDGE.

T

was opened for highway traffic January 26th, 1893; but the amount ofhighway traffic has not proved enough to pay the expenses of collectingthe tolls or in any way to interfere with railroad traffic.

On the 31st of December, 1892, all work, except the pavement ofthe east bank and some riprap protection, being completed, the care ofthe bridge was turned over to Mr. W. A. Nett let on, Superintendent ofTerminals. On the 1st of May, 1893, this other work also being com-pleted, everything was placed in his hands.

II.

GENERAL DESCRIPTION.

The Memphis Bridge and approaches, being the entire line of rail-road owned by the Kansas City and Memphis Kailway and BridgeCompany, extend from the connection with the main line of the KansasCity, Ft. Scott & Memphis Railroad in Crittenden County, Arkansas, toa connection with the tracks of the St. Louis, Iron Mountain & SouthernRailway on the west side of Kentucky Avenue in the city of Memphis,Tennessee, a total length of 15 903 feet, or 3.01 miles.

For convenience, a point arbitrarily selected on the east bluff wasmade the starting-point for all measurements and numbered Station 100.

The point of connection with the Kansas City, Ft. Scott & Memphistracks is at Station 230 + 35 and the connection with the rails of theSt. L., I. M. & S. Ry. at Station 71 + 32. At Station 187 + 46.4 theline crosses the main track of the St. L., I. M. & S. Ry. in Arkansas andconnection is made with that railroad. At Station 209 + 61.5 the linecrosses the main track of the Little Rock & Memphis R.R. and connec-tion is made with that railroad. At Station 76 + 71 the line crossesKansas Avenue in the city of Memphis and connection is made with thetracks of the Kansas City, Ft. Scott &, Memphis Railroad, which are laidin that street.

The entire railroad is a single-track line, excepting between the eastend of the bridge and Pennsylvania Avenue, where there are two tracks.East of Pennsylvania Avenue one of these tracks forms a connection forthe St. L., I. M. <fc S. Ry.

Two long side tracks, which form the basis of a west side yard, have

been put in immediately west of the crossing of the St. L., I. M. & S. Ry.,and a station has been established here named Bridge Junction.

The total amount of track laid and belonging to the Kansas City &Memphis Railway and Bridge Co. is 20 990 feet, or 3.98 miles. Thelength of track belonging to the Bridge Company and used by the KansasCity, Ft. Scott & Memphis R. R. is 19 166 feet, or 3.63 mile's. Thelength of track used by the St. L., I. M. & S. Ry. is 11 668 feet, or 2.21miles.*

The East Approach ascends to the bridge with a grade of 1.31 percent (69.17 feet per mile), this maximum grade being 1200 feet long, buta total ascent of 26 feet is made in 2500 feet.

The West Approach ascends to the bridge with a grade of 1.25 percent (66 feet per mile), the total ascent being 77 feet, all of which ismade in a uniform continuous grade varied only by vertical curves at thetwo ends.

The general location is given on Plates 1 and 2. The grades andalignment are shown on Plate 3.

The entire line thus briefly described may be divided into fourparts:

1. The East Approach, including everything east of the East Abut-ment.

2. The Bridge proper, extending from the East Abutment to Pier Vinclusive.

3. The Viaduct, extending from Pier V to Pier 54.

4. The West Approach, extending from the viaduct to the connec-tion with the Kansas City, Ft. Scott & Memphis Railroad in Arkansas.

These several parts will be more fully described hereafter. Thebridge crosses the Mississippi River in latitude 35° 8' and longitude90° 5', 232 miles below the confluence of the Mississippi and Ohio riversat Cairo, Illinois. It is the first bridge built across the real Mississippi.

The Mississippi is really formed of four great tributaries. The twoeastern branches are the Ohio and Tennessee rivers which unite atPaducah, Ky., forming a single river only for 50 miles, from Paducahto Cairo. They are both rivers of stable regime, but subject t® extremefloods.

The two western tributaries are the Mississippi and the Missouri,which come together near Alton, Ill., forming a single river for about

* These lengths of track are the amount laid at the time I gave up control of the work. Somefurther additions have since been made by the Operating Department.

200 miles. They are rivers of very different character, the Mississippibeing a quiet stream of comparatively stable character and the Missouria silt-bearer of the first magnitude. The Missouri gives the character tothe united river below the junction. It is a silt-bearer subject to floods,but not to as violent floods as those in the Ohio.

Of the four great tributaries, the Missouri must be rated as thegreatest, and the Mississippi as the least. The Mississippi and the Mis-souri combined into one river form a stream of about the same size as theOhio and Tennessee combined into the Ohio. Where the two great riversunite at Cairo they are of about equal magnitude.

Though these two great rivers are of about equal magnitude, theyare of very different character, and the Mississippi proper below Cairofeels the effect of both. Like the Missouri, it is a great silt-bearer. Likethe Ohio, it is subject to extreme floods. As is always the case whenmagnitude is increased, the changes in channel and the local disturb-ances are much less rapid than on the Missouri, but they are of the samecharacter, and on a much larger scale. The floods which are most activeand dangerous come from the Ohio. The flood season in the Ohio is inthe winter and early spring; the flood season of the Mississippi andMissouri is in the spring and early summer; the flood season of the tworivers covers about one half of the year, extending from about the first ofJanuary into July. The whole working season which can be safely de-pended upon in the Lower Mississippi covers only about five months ofthe year.

The flood stages are shown graphically on Plate 6. In studyingthis plate it must be remembered that every flood which occurs at Mem-phis is really a flood of the river itself, there being no great tributarybelow to cause backwater, and every flood being accompanied by a rapidcurrent.

The strongest current ever actually observed was on March 20th,1890, being at the rate of Ilf feet per second, or eight miles per hour.The usual average current was perhaps three miles per hour, this, how-ever, being largely conjectural. In extreme low water there were timeswhen the current was less than a mile an hour; fortunately one of thesetimes occurred during the placing of the caisson for Pier II.

Levels were connected with the benches established by the Missis-sippi River Commission, and all elevations referred to the datum plane ofmean tide-water at Biloxi, as given by those benches.

The Government gauge at Memphis is at the foot of Jefferson Street9600 feet, or 1.82 miles, above the bridge. Gauge-readings were kept dur-