Case Study: Southern Cross Station — 13 Visits in 14 Days

Summary

Spencer Street Signals Section 1101 visits Southern Cross Station 13 times in a 14-day period (4-18 July 2026) to perform 42 work orders. Across the full year, this team visits Southern Cross on 87 separate days to complete 316 work orders. This example demonstrates the scheduling pattern at a major CBD station where the volume of assets generates a near-daily visit from the same team.

The Schedule (4-18 July 2026)

Date	WOs	Job Types	Asset Type	Notes
Sat 4 Jul	6	SP327, SP329, SP001	Point Mechanism	Point inspections at 2 sets
Sun 5 Jul	2	SP201	Interlocking	Relay shelf inspections
Mon 6 Jul	1	SP322B	Point Mechanism	Single point mech check
Wed 8 Jul	3	SP201	Interlocking	Relay shelf inspections
Thu 9 Jul	5	SP201, SP368	Interlocking, Train Detection	Relay inspections + train detection
Fri 10 Jul	5	SP322B, SP201	Point Mechanism, Interlocking	Point checks + relay inspections
Sat 11 Jul	1	SP201	Interlocking	Single relay inspection — entire day
Sun 12 Jul	3	SP368, SP201	Train Detection, Interlocking	Train detection + relay inspection
Mon 13 Jul	2	SP327A	Point Mechanism	Point inspections
Tue 15 Jul	1	SP201	Interlocking	Single relay inspection — entire day
Wed 16 Jul	3	SP201	Interlocking	Relay shelf inspections
Thu 17 Jul	2	SP201	Interlocking	Relay shelf inspections
Fri 18 Jul	8	SP327A, SP322A	Point Mechanism	Point inspections at multiple sets

Map shows Southern Cross work orders (4-18 July) colour-coded by day. Marker size indicates WO count. Click markers for details.

Why 13 Visits?

Southern Cross is one of the largest and most complex stations on the network, with a high density of interlocking relays, point mechanisms, and train detection equipment. The work orders are dominated by two job types:

SP201 — Relay shelf inspection (732-day frequency, 73-day tolerance): 19 of the 42 WOs. These have an enormous tolerance window (approximately 5 months) but are spread across 9 different days.
SP327A / SP322A / SP322B — Point mechanism inspections (21-30 day frequency, 3-6 day tolerance): 17 of the 42 WOs. These have tight windows that constrain when they can be done.

The scheduling issue is that the SP201 relay inspections — which have a 5-month window — are placed one per day at their midpoints, creating a daily drip-feed of work. On 3 of the 13 days, the team comes to Southern Cross for just a single SP201 relay inspection.

The Tolerance Windows

Job	Frequency	Tolerance	Window Size	WOs in period
SP201	732 days	73 days	~5 months	19
SP327 / SP329	61 / 183 days	6 / 18 days	12-36 days	6
SP327A	21 days	3 days	6 days	7
SP322A / SP322B	21-30 days	3-6 days	6-12 days	7
SP368	366 days	36 days	72 days	3

The point mechanism jobs (SP327A, SP322A, SP322B) have tight 6-12 day windows and genuinely constrain the schedule. But the SP201 relay inspections could be moved anywhere within a 5-month window, and the SP368 train detection jobs have a 72-day window.

What an Optimised Schedule Would Look Like

An optimised approach would anchor visits around the tight-window point mechanism jobs and batch the flexible SP201 and SP368 work onto those same days:

Date	WOs	What changes
Sat 4 Jul	6 + 2 = 8	Add Jul 5 relay inspections
Mon 6 Jul	1 + 3 + 1 = 5	Add Jul 8 relay inspections + Jul 11 relay
Thu 9 Jul	5 + 3 = 8	Add Jul 10 point checks (windows overlap)
Sun 12 Jul	3 + 1 = 4	Add Jul 15 relay inspection
Mon 13 Jul	2 + 3 + 2 = 7	Add Jul 16-17 relay inspections
Fri 18 Jul	8	Already a full day

This reduces 13 visits to 6 — a 54% reduction — while keeping all work within its tolerance window. The heaviest day would be 8 WOs, well within normal team capacity.

The Scale of the Problem

Across the full year, Spencer Street 1101 visits Southern Cross on 87 separate days to do 316 work orders — an average of just 3.6 WOs per visit. With optimised batching, this could be reduced to approximately 30 visits averaging 10-11 WOs each, eliminating over 50 unnecessary mobilisations to the same station.

Relevance

This case study is significant because:

It's at a CBD station — Southern Cross is one of Melbourne's busiest stations. Every maintenance visit requires coordination with station operations, and reducing visit frequency directly reduces disruption.
The flexible jobs are being treated like rigid ones — SP201 relay inspections have a 5-month window but are scheduled as if they must happen on one specific day. The system makes no attempt to batch them with other work at the same station.
The tight-window jobs provide natural anchor points — the 21-30 day cycle point mechanism checks create a regular cadence that the flexible work could be attached to, rather than scheduled independently.
The pattern is consistent — this isn't a one-off scheduling anomaly. The same near-daily visit pattern occurs throughout the year at Southern Cross, and similar patterns exist at other major stations (Flinders Street, Richmond, North Melbourne).