TRN stands for Train Run Number, different from trainset
number. It's located at the top right corner of the train
ends. TRN is constant depending on the day. For example, Monday and
Tuesday are working days. At 6.45am, the train arriving Tampines
heading WB has TRN029. The next day, the TRN will be the same at
the same time slot.
However, if it is a Saturday, the 6.45am train arriving Tampines
heading WB may not be TRN029, as Saturday is not a working day for
most ppl, so frequency stands at 4-6mins.
P.S. Different trains may run the same TRN on different days.
For e.g. On Monday, 001/002 has TRN029, on Tuesday, it could be any
other train or it could even be 001/002 again with TRN029.
Come to talk about that, should we compile a table of which the
trains arrive on weekdays and weekends. That way, it'll be way much
easier to do train spotting as you will know when the particular
train arrives. Agree?