File 1702/1910 Pt 1 'Railways: Persia; Khoremabad-Dizful-Mohammerah Railway' [‎188v] (124/546)

24*
87. Third Section. QaVeh Jttza (1,550') to Ziarat Ahmed KuchiJeeh.
(1,950') 14 miles,—l select Ahmed Kuchikek as the end of this section because
it is a ruling point through which any alignment must pass, being the lowest
point of a saddle formed by an extension of the slopes of the Kabir Kuh across
the valley : the Saidmarreh river forces its way through the obstacle thus placed
in its way by a deep gorge : the edge of the ravine being some 200' higher than
the proposed alignment.
Between Qal’eh Riza and Pul-i-Tang (9 miles! two alternative alignments
present themselves : the hrst keeps to the northern side of the Qal’eh Riza plain,
crosses the Zal just below the point where it entei s the plain, near an ancient
(probably Sassanian) high-level bridge or aqueduct and keeps to the foot of
the gypsum hills, crossing the Ab-i*Tirada, and lour large ravines, till it
debouches on to the gentle lime-stone slopes near Pul-i-Tang.
The advantages of this alignment are (1) it does not descend below 1,350';
(2) it is probably one mile shorter than the alternative route ; (3) it does not
cross the Saidmarreh; (4) a gradient of 1 in 100 could in all probability be
obtained, though at great cost: its disadvantages are (1) not less than six
bridges of some size; (2) heavy cutting for about 2 miles, alternatively with
heavy embankments ; (3) awkward curves round gypsum spurs ; (4) hills travers
ed between Tirada and Pul-hTang are gypsum which is rapidly corroded by
water and which blasts badly, being of very unequal consistency.
The alternative alignment keeps to the south side of the Qal’eh Riza plain :
crosses the Saidmarreh at 1,300' just below its junction with the Zal and Tirada
streams : continues over the flat stony plain of Siyah Gilal, and re-crosses the
Saidmarreh at 9 miles near Pul-i*lang (1,300 ). This aligment has the follow
ing disadvantages ; (1) it reaches a level 50 lower than the first mentioned line;
(2) it involves two bridges across the Saidmarreh ; (3) it involves^ a gradient
of between 1 in 50 and 1 in 75 between Pul-i-Tang (1,300 ) and Ziarat Ahmed
Kuchikeh (1,950'), a rise of 450' having to be distributed over about 5 miles.
A 50' cutting through the gypsum at Ziarat Ahmed Kuchikeh will assist matters,
and a slight increase in length can be arranged for so as to diminish the slope,
but the best that can be expected is 1 in 7 5. There will be no difficulty in
keeping an even gradient from Pul-i-Tang to Ahmed Kuchikeh, as for the whole
distance the line will cross gentle lime-stone slopes. Its advantages are (1)
cheapness : I think it will be found that the cost of the two bridges is amply
compensated for by the lack of heavy works elsewhere : (2) rapidity of construc
tion : the heavy cuttings through the gypsum hills will take a long time as also
will the bridging of the ravine.
It will necessitate the following bridges :—
(1) Across Saidmarreh below the Zal junction : steep but not precipi
tous. The river is here 150' to 200' broad: banks 60 to 80 high:
bed rocky : depth unknown, probably not over 10' in summer:
width from bank to bank about 450\
(2) Across Saidmarreh near Pul-i-Tang. The river here flows through a
deep gorge 6' to 10' broad at bottom, 12' to 20' at top, but no
more than S' broad in places : it is bridged by a single span stone
bridge: a bridge some 250 yards long would be necessary but no
spans need be longer than 20'.
Gradient .—Prom Qal’eh Riza to Saidmarreh 1 in 100 can obtained without
difficulty. Prom Saidmarreh to Pul-i*Tang level: from Pul-i-Tang to Ziarat
Ahmed Kuchikeh 1 in 75.
Curvature. throughout.
Formation of growwc?.—Riza plain : stony alluvium.
Siyah Gilal: do.
Pul-i*Tang-Ahmad Kuchikeh: gentle limestone
slopes inclining 4° to south : no soil available :
no large ravines to cross or other awkward fea
tures.