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Old 15th February 2018, 06:58
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aussiesteve aussiesteve is offline
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Join Date: Dec 2017
Location: Bathurst
Posts: 577
G'day,
Just found this thread and will toss in my two bob's worth.
Here in NSW we have three specific train speed boards in use as distinct from temporary speed restrictions.
Where the high speed XPT wanders, there will be a silver board denoting the sectional speed for it.
Where medium high speed DMU trains operate, there will be a blue board denoting the sectional speed for such.
And, all track sections have the yellow board which denotes the sectional speed for locomotive hauled trains.
The yellow boards may indicate a relatively high sectional speed, up to a maximum of 115 kph.
But, that does not indicate that freight trains can percolate at such speed.
Only high wheeler freight with high speed bogies through-out the train can operate at top locomotive hauled speeds.
Most freight is limited to a maximum of 80 kph.
And certain slow speed bogies restrict the speed further.
The train crew must know the specific speed permitted for their freight consist.
Light Engine movements are also limited to a maximum sectional speed.
Locomotives are heavy and will take longer to stop if travelling at high speed.
This is determined by the locomotive brake type.
Some locomotives only possess one brake block per wheel, while others possess two brake blocks per wheel.
The single brake block per wheel design is to prevent the wheels from locking up and skidding.
When descending steep grades Light Engine, it is a general requirement that the locomotive have a working dynamic or regenerative brake.
Where trackwork has occurred, or due to a track defect, a temporary speed restriction is applied.
Again, two small speed signs may be attached to advise of the speed for loco hauled trains or the XPT.
The XPT sign will indicate a slightly higher speed limit to that for the loco hauled.
Where no DMU sign is utilized, any DMU train must travel at the loco hauled speed indicated.
Our temporary speed restrictions may also possess a time sign.
The time sign indicates the period during the day when the speed restriction applies.
This generally being the case during summer and hot temperatures.
Steve.
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