A brief description of the corridor №2

The Modjo – Shashemene – Awasa, Konso – Weyto, Konso – Moyale sections of the Modjo – Moyale railway line have been preliminary designed according to the instructions of ERC. Moreover, the trackbed along the Modjo – Shashemene section of the line will be suitable for a double track, while the rest of it – for a single track. The maximum gradient is 18‰. The minimum curve radius is 800m. Considering the exceptionally difficult topography between Konso and Weyto the 500m minimum curve radius is adopted.

A junction arrangement at Modjo is necessary in order to connect the 2^nd and 1^st corridors. Also, there is a necessity for a junction at Moyale in order to connect the 2^nd corridor with the Kenyan railways.

The railway junctions are to be located considering:

- the detailed design of the railway corridor 1;

- passenger and freight traffic volume along the connecting corridors;

- convenience to perform passenger and freight operations;

- topography, geology and hydrology of the land allocated for the junction, etc.

It is anticipated that the shunting stations (dry ports) will be located near the large settlements such as Modjo, Shashemene, Konso, Weyto, and Moyale in order to perform all types of freight and passenger operations, as well as service the rolling stock.

Also, according to the preliminary study, 7 intermediate stations are anticipated along the proposed corridor in the vicinity of Ziway, Awasa, Sodo and other towns and the freight and passenger operations will be performed there.

It is anticipated that 21(first order) and 23 (second order) passing loops will be constructed to ensure the specified line capacity.

The number and classes of passing loops were determined on the basis of the preliminary capacity assessment provided by ERC.

Proceeding south with the slight deviation in the western direction the Modjo – Shashemene – Awasa alignment of the 2^nd corridor passes close to Koka, Alem Tena, Meki, Abosa, Ziway and etc.

The alignment is surrounded on the both sides by several large lakes - Koka, Ziway, Abijatta, Langarno, Shalla and Awassa.

In the vicinity of Shashemene the alignment sharply turns west – north–west. Reaching Alaba Kulite, it returns to its previous direction. Bypasses the high altitude topography between Budti and Sodo in the west and slopes to Abaya Lake. Passing along Abaya Lake, it moves beyond Irae, Milirab Abaya and Arba Minch. Then, down the Chamo lakeshore, the alignment bypasses a high plateau with Konso situated there, which is 5 km away from the Manda town in the east.

After Konso the railway line proceeds south–east to Yabello, bypassing it from the side of Yabello National Park. Then it moves north–east beyond Mega and reaches Moyale on the Kenyan border.

The Konso – Weyto track alignment has been planned along the rift valley that represents a nullah.

The vertical alignment of the preliminarily designed railway line is mostly represented by embankments which reach 0.5-5m high, or the absolute height of 25m on the certain sections of the line, and cuts which reach the absolute depth of 32m. These sections require an additional reviewing to optimize its position.

An additional survey to revise the alignment position of the Alaba Kulite – Sodo – Irae and Konso – Weyto sections are necessary to minimize the works and construction price.

Due to utterly difficult topography around Konso, Yabello and Mega and failure to find any reasonable solution for the railway line to reach them without incurring unjustified costs, as well as to locate passing loops and stations, the alignment has been shifted to the side for about 5–10km.

The number of engineering structures for the considered routes determined according to the preliminary assessment based on the analysis of 1:50,000 maps and high-resolution satellite images (1m) is shown below:

- culverts - 3416;

- bridges - 65;

- tunnels - 2.

A summary of key specifications is provided in the table below:-

№	Item	Unit	Quantity
	Track length:
	- Modjo – Moyale	km
	- Shashemene – Awassa	km
	- Konso – Weyto	km
	Total track length	km
	Actual track length/shortest distance ratio	-	1.55
	Minimum curve radius:
	- Modjo – Moyale	m
	- Shashemene – Awassa	m	2,000
	- Konso – Weyto	m
	Combined angles of circular curves (∑ )	degree	9,449
	Curves per km or percent of curves	km / %	267.8 / 27.4
	Average curve radius	m	1,624
	Number of stations and passing loops:
	- Shunting stations	ps
	- Intermediate stations	ps
	- Passing loops
	I order	ps
	II order	ps
	Engineering structures:
	- Bridges	ps
	- Tunnels	ps
	- Culverts	ps	3,419
	Earthworks per km (average)	ths.m^3/km
	Total earthworks (preliminary estimated)	ths.m^3	44,616

N.B. ps – pieces; ths. – Thousand.

The further revision of the position of the track alignment along the 2^nd corridor is possible after the detailed topographical survey, geological and hydrological surveys, land use information and other pertinent data are provided.

The preproject designs of the Modjo – Moyale, Shashemene – Awassa and Konso – Weyto railway lines have been prepared based on satellite images and 1:50,000 maps using current design standards for new railway projects.

Given materials have been processed using the following software:

- EasyTrace

- Topomatic–Robur–Survay

The horizontal and vertical alignments have been prepared using specific software called Topomatic–Robur, which is utilised to design rail and automobile roads and engineering structures.

Дата добавления: 2015-07-20