"XXII\٨ سكة حديد بغداد" [و‎‎٣‎٦] (١٩٤/٧٠)

[426] E 3
Attached to this plan shall be : a longitudinal profile following the central line of
the railway, a certain number of type cross sections of the bed of the railway, a table
of the rising and falling gradients, and drawings of the most important engineering
w r orks.
The longitudinal profile shall be drawn to a scale of 5 - ( fo(T horizontal and - 5^0
vertical, the levels of which shall be referred to the mean sea level as a datum-line ;
below the profile thei'e shall be indicated, by means of three horizontal lines drawn for
this purpose :—
(a.) Distances of 1,000 metres each along the railway from its starting point;
( 6 .) The length and the rate of the gradients;
(c.) The length of the tangents and the graduation of the curves of the line,
showing the radius of each of these latter.
The concessionnaires shall further submit a general plan to a scale of Tdoooo? an d a
longitudinal profile drawn to a horizontal scale of toWoo anc ^ a vertical scale of yoVo*
Art. 3. The works shall be carried out for a single line.
Art. 4 . The width of the gauge inside to inside of the rails shall be from
D435 metres to 1’455 metres.
The sidewidths, i.e., the portions of the permanent way comprised on either side
between the outer edge of the rail and the edge of the ballast at the top, shall be not
less than 1 metre for a single line ; if there is a double line the intervening space shall
be 2 metres wide.
Art. 5 . The concessionnaires shall construct along the railway such ditches, gutters,
and small banks as shall be deemed necessary for the drainage of the track and bor'row-
pits, and the maintenance of the w r orks.
The ballast shall have a thickness of 0-40 metre, and the sleepers shall be of metal.
The formation width beneath the ballast shall be 5‘50 metres. This width may be
reduced to 5 TO metres in the difficult portions of the line. It may even be reduced to
4'50 metres when the ballast walls rest on masonry or solid rock.
Art. 6 . The tangents shall be connected by curves, the radius of which may not
be less than 500 metres. A tangent of 100 metres must be inserted between two
reverse curves.
The curves must further be joined to the tangents by means of a parabolic curve,
■which must encroach on the straight portion for half its length. The length of tangent
remaining between the commencement of the parabolic curves may then be reduced to
10 metres on condition that the radius of curvature is increased as much as possible.
Art. 7. The normal maximum rate of the rise and fall of the gradients is fixed at
18 millim. per metre.
The junctions of the gradients shall be effected by means of vertical curves of a
radius of 1,000 metres.
The gradients corresponding to curves of small radius must be reduced as much
as possible.
The concessionnaires shall have the right to propose such modifications as may
appear to them useful to the provisions of this article and those of the article preceding
it, i.e., a reduction of the radii of curvature to 300 metres, and an increase in the
gradient to 25*8 per mil in those parts which present special difficulties. But such
modifications can only take effect after they have been approved by the Imperial
Government, and in so far as they do not prevent, in case of need, an average speed of
75 kilom. an hour, including stops, over the whole line.
Art. 8 . There must be a sufficient number of passing-places and sidings for standing,
loading, and unloading, and they shall be determined by the Government on the proposal
of the concessionnaires. It is hereby provided that the average distance between the
stations shall be about 20 kilom. The length of the passing-places shall not be less
than 300 metres measured between the fouling-points. In grading the longitudinal
profile care shall be taken to provide level stretches of sufficient length in places where
new stations are likely to be subsequently built.
Art. 9 . When the railway has to cross roads or tracks, the preservation of which
is necessary for the communications of the country, subways, bridges, or level crossings
shall be constructed according to the configuration of the ground.
When the railway has to be carried over a road, the span of the viaduct shall
be fixed by the Government, with due regard to local circumstances, on the proposal
of the concessionnaires, and may vary from 3 to 10 metres.
In the arched viaducts the headway below the keystone of the arch from the road