The Railway-Tracks of Srilankan Railways are a shining teaching sample that a long-lasting well aligned rail-track, matching the traffic load it has to carry, is not possible without a well drained and well bearing Formation, a thick Formation Protective Layer (FPL, “Blanket” or “Sub-Ballast”) and a proper and clean Ballast-Bed. The memory for the track misalignments in Sri Lanka is mostly buried in the poor bearing and badly drained or even missing formation. The biggest obstacle for the Colombo Suburban Railway Project, to make the track fit for faster and more frequent commuter service, are not the current 90 pound rails but the poor bearing, yielding, poor drained and unstable formations, or even the missing formation, and the improper and poor ballasting. Envisaged long-welded UIC 60 rails alone will not do the job; see: COLOMBO BACKS RAIL TO TACKLE CONGESTIONS by Keith Barrow, in International Railway Journal, August 2018, page 30.
If there is nearly no ballast or only marginal ballast and hence the Load Distribution not sufficient, the concrete sleeper will “dance” under dynamic traffic load, hammer the few ballast stones into the formation, formation material will prop up, and the marginal ballast stones get either crushed to dust or submerge in the formation. Overloading of formation due to missing ballast and missing formation protective layer cause soil to penetrate into ballast vice versa. Formation material and ballast are mixing. This happens all over insufficient ballasted SLR Tracks.
Envisaged electrification will not bring alleviation for the current low route capacity and low train speed, if not the rail-tracks from Kalutara up to Negombo and Rambukkana will face comprehensive formation re-engineering, rehabilitation and strengthening, as well proper ballasting. The current poor quality rail-tracks need constant and costly maintenance and repair – “nearly as every train goes” = former GMR Mr. Priyal De Silva – .
To read more, download: BALLAST and FORMATION, revised 3, PDF