A
—
(b) In the design stage, to determine the cross section of the ground before construc-
tion and to compute the design quantities, vertical curves, gradients, super-elevations,
slope stake information and related data.
(c) In the construction stage, to determine the cross section of the right of way at
different stages of construction and also to determine the cross sections of the finished
road bed; to compute progress and final pay quantities, and to provide an evaluation
of the constructed grade.
2. INSTRUMENTA TION
In the integrated system developed by our staff, the following instru-
ments are used: -
Wild RC-8 aerial camera with 6" Avigon lens
Kelsh plotter with a digital read-out attachment
Wild A-8 Autograph with EK-3 Co-ordinate
Printer and Profiloscope
Electro Dataplotter
IBM 650 Computer
We have modified the Kelsh plotter to provide means of measuring
accurately one plane co-ordinate (the distance to the left and right of the center line)
and to permit automatic punching on tape of this reading of thedevation. This modified
plotter is shown in Fig. 2. To determine the cross sections, the arm is placed
perpendicular to the center line as drawn on the manuscript and then the tracing
table is moved along the designed cross section by rotating the lead screw. By
pressing a button the station number, the distance from the center line and the ele-
vation of the desired point are automatically punched on a tape.
Alternatively, we employ the Wild A-8 Autograph equipped with a
Profiloscope and coupled to an EK-3 Co-ordinate Printer. The Profiloscope permits
convenient viewing by the operator of the manuscript and eliminates the use of a
table man. The output from the EK-3 Co-ordinate Printer is in the form of a tape
in a 5-channel teletype code and also in typewritten form.
In initial tests with the Kelsh plotter and the Wild A-8 with EK-3,
the latter instrument was found to be in our overall evaluation, more economical
in spite of its higher purchase price.
The Electro Dataplotter is basically a coordinatograph which
performs the automatic drawing of cross sections or any other mathematical func-
tion which can be expressed in the form of x and y co-ordinates. The cross sections
are drawn automatically from punched cards. We employ an IBM Type 526 Summary
Punch as a card reader. The Dataplotter requires instructions for each change made
in operation and for each change in pen position. These instructions are supplied by
means of control code punches.
3. ESTABLISHING OF HORIZONTAL POSITIONS I
The methods we employ to establish horizontal positions for rail-
way location studies are bridging procedures which make use of numerical photo-
grammetry. (A detailed discussion of this method would concern Commission III,
and therefore, only a brief description of its practical application and its results
will be given in this paper.)
