(Cross-posted at bus interchange / terminal thread)
After some thought, I shall refine my original suggestion a
little - putting it down to three semi-independent schemes that may
still increase the efficiency overall.
The map is here: https://www.google.com/maps/d/edit?mid=zEEpmI3uw7s8.k1cLkPzdzugo&usp=sharing
Here goes:
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Scheme A: Amendment of 857 (or some other
suitable Yishun trunk)
This amendment makes good use of the DDs added to the 857 fleet
to cover the link between Yishun Ave
4 (incl. the schools along the way) and Khatib MRT.
The extended stretch from Ctrl 2 to Khatib MRT is about 2,240m,
an increase from the current
undiverted 978m by about
1,262m or 1.26km. Two pairs of bus stops are skipped (with
alternative service 855) in favour of six pairs of new stops.
Using 857 is tentative, of course, but it would be best to
employ one with decent frequency (to match 812) as well as having a
HC (bendy / DD) fleet.
Scheme B: Amendment of 85
This amendment makes good use of the DDs added to 85 fleet to
cover the link between Yishun St 61
and Khatib MRT. The extended route is about 1.7km, an
increase of about 1km from the
current 700m undiverted route. It disregards the territorial
concerns between SMRT and SBST, and maintains the link to
Northpoint, while skipping only one pair of bus stops in favour of
six pairs of new stops.
As a result of this change, 858 will skip Yishun Ctrl 1
& 2 to reduce problems for its
bendys. Without 85, an alternative (and somewhat faster)
link to Jln Kayu and Punggol is provided by 117.
Alternatively, this route amendment may be carried out on 117,
in the event that it could cause traffic disruptions or demand
problems on 85.
Scheme C: Amendment of 812 (East loop)
As a consequence of scheme A, or both A and B, 812's east loop
will be less stressful / in demand. The change will allow the
service to skip the northern section
of Ave 4 (served by
857), and serve the newly
developed areas at St 51 / 52. The bus stop at Blk 322 is
still within walking distance to the bus interchange (for 857), to
maintain the link to Ave 4.
Making use of 812 also eliminates the need to introduce a brand
new feeder service to St 51 / 52 / 41, thus saving a berth at
Yishun Temporary Interchange.
The extended route is very tentative and subject to changes.
It may not necessitate implementation until the
new estates are ready.
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Btw - any comments?