Saturday, November 30, 2013

SMRT - concrete sleepers

SMRT are replacing the wooden sleepers with concrete ones in their major overhaul maintenance. They should give the public a cost comparison and detail of advantages between timber vs concrete sleepers.

Some time back, there was an allegation that SMRT used sub standard timber when replacing the current failing wooden sleepers. SMRT has refuted the allegation as untrue.  Since SMRT is capable of using plastic cable ties to hold parts together,  the public cannot be blamed for having doubts in SMRT selection of timber quality.

Now they announced they are using concrete sleepers, one wonders the reason behind it. Could it be cost consideration?  Timber sleepers are better sound and vibration absorber compare to concrete. Besides - they are lighter.

Hope SMRT has done a thorough load calculation of the concrete sleepers on the overhead MRT tracks which are supported on pillars.  Likely the concrete sleepers would have reinforced steel bars in them which increased their weight further.

Still fresh in our mind are the major breakdowns due to increased passage load and frequency of trains over stressing the train rails. Now there will be another new stress factor from concrete sleepers on the overhead tracks and rails.  It may have an impact on the structure integrity over time, especially if its original design is meant for wooden sleepers.

So looks like the money SMRT spend to upgrade the train's drive system to a quieter one will be undone by noisier concrete sleepers.  Jerkier train ride in future too ?

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