Bus Service Prefixes and Suffixes

In Singapore, alphabetical Prefixes and Suffixes are sometimes attached to bus service numbers. These can be used to identify special types of bus routes, or to indicate route variants of their parent service.

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A, B, C — Short Trip Services

Suffix used for supplementary trips which ply segments of their parent route rather than the full route of their parent service. Due to the lengthy nature of most bus routes, Short-Trip services are needed to cater to specific route sectors, rather than improving bus frequencies throughout the route. This helps to better allocate resources to where they are needed.

Most Short-Trip services operate during peak hours, connecting various transport nodes (i.e. MRT station/bus interchange) with residential estates, industrial areas or educational institutions. Other Short-Trip services operate late at night, after the last bus of their parent service has departed. These services usually cater to residential sectors of long trunk routes, or half-trips of longer loop services. Finally, there are Short-Trip services that only operate on weekends and special occasions, catering to unique sectors of route encountering high demand. Some Short-Trip services fall into more than one of these categories.

Bus Services 138C, 268C, 962C, 975C and 991C are currently the only Short-Trip Services with the ‘C‘ suffix.

Several bus routes share the A/B suffix of Short-Trip services, but have unique operating patterns:

Service(s)	Description
179A, 502A, 518A	Semi-express bus routes that skip selected stops of the parent route
859A/859B, 912A/912B	Route variant operating throughout the day; suffix used to indicate directional loop

A full list of Short-Trip Services in Singapore can be found at Short-Trip Services | Land Transport Guru.

 

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E, e — Express Services

Suffix used for Express Bus Services, which are bus services that contain express sectors by skipping bus stops or travelling by expressways. This reduces commuting time as compared to regular trunk services. These services charge Express fares as they serve smaller catchment areas while providing reduced travel time and added convenience.

Uppercase ‘E’

Used to denote peak hour express services (not exhaustive).

Lowercase ‘e’

Used for Limited-stop express services that closely mirror their parent route, but call at fewer bus stops along the way (often incorporating express sectors along expressways/trunk roads). First introduced as Fast-Forward Services by SBS Transit, and later rebranded as Express services after a renaming exercise on 13 August 2018. Limited-stop routes introduced by SMRT Buses (188e, 854e, 963e), formerly using the uppercase E, were renumbered with the lowercase e for standardization.

The Uppercase ‘E‘ suffix (for ‘Ending’) was formerly used for terminating trips on SMRT Intratown services. This has since been renumbered to the ‘T‘ suffix. More information at the T suffix section below.

 

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G, W — Green Plate / White Plate (Directional Loop)

Suffix used by SBS Transit to designate the clockwise and counter-clockwise directions of a loop service (e.g. A→B→C→A and A→C→B→A). G and W stand for Green Plate and White Plate. In the past, buses carried plastic/metal destination plates, and the green/white background was used to assist commuters in easily identifying the direction of travel. On modern buses with electronic display signs, the G and W suffix is used instead.

The A and B suffixes are also used for directional loop services. Examples are 859A/859B and 912A/912B.

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LCS — ‘Loyang-Changi Shuttle Service’

Prefix used for two peak-hour shuttle bus services operated by SBS Transit: Bus Service LCS1 and LCS2.

These services serve Loyang Industrial Estate (LIE), Airport Logistics Park of Singapore (ALPS), and Changi Airfreight Centre (CAC).

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M, X — ‘Modified’ / Route Variant

Suffix used for route variants of a particular bus service, plying a modified version of the parent route. Route variants can operate either alongside their parent service throughout the day, or have operating hours staggered with their parent service. Historically, route variants have been referred to using a variety of suffixes, such as A or B, C, W, X, or #. Most route variants have been standardized to the ‘M‘ suffix, but exceptions still exist (enclosed in parentheses).

Service(s)	Description
43M, 53M, 63M, 98M, 123M, 143M, 901M, 913M, 972M (170X)	Full-day route variants
35M, 70M, 107M	Replaces parent service on Weekday nights, Saturdays (Afternoon/evening till end of service), Sundays & Public Holidays (Full day)
853M, 925M, 961M	Replaces parent service on Sundays/Public Holidays (Full day)
240M, 903M, 912M, (502A, 518A), 983M	Peak hour route variants, operating alongside parent service
883M	Weekend/PH route variant, operating alongside parent service
117M, 181M, 182M, 248M	Replaces parent service during selected times of day
16M	Operates as alternate departures of parent service

Some route variants like 53M and 123M do not share the route termini of their parent service. Bus services 170X, 502A and 518A are included in the above list as their operation pattern closely matches that of existing route variants, although they retain their non-M suffixes.

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X — Express Feeder Variant

Suffix used to denote Express Feeder bus services, plying an express variant of the parent Feeder bus service. These services were introduced under the Land Transport Authority’s Bus Connectivity Enhancement Programme (BCEP) launched in 2024.

Service	Route
298X	Tampines North Bus Interchange ↺ Tampines Street 86 (Loop)

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T — Terminating

Suffix used for the terminating trips of two-part Feeder bus services that perform continuous loops (A→B→A→C→A repeatedly). These two-part Feeder routes were formerly known as Townlink (SBS Transit) or Intratown (SMRT Buses) routes. Displaying the T suffix indicates that the bus will terminate at the interchange and no longer continue on the next loop.

Historically, SBS Transit used a ‘T’ sign at the front of the bus, while SMRT Buses used the E suffix on the electronic display signs of their buses. These have now been standardized to the T suffix on all electronic display signs.

In April 2021, the T suffix was used to denote terminating trips of loop services at bus interchanges / terminals.

Services 36 & 92 are the only trunk services operating in a continuous-loop fashion.

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EB, GA, TT, WT — Employee Bus Services

Prefix used for Employee Bus Services, which are scheduled bus services run by Public Transport Operators as a means of transporting employees.

SBS Transit uses the prefix ‘EB‘ for Employee Bus; SMRT Buses uses the prefix ‘WT‘ for Worker’s Transport. Similarly, Tower Transit Singapore and Go-Ahead Singapore use the prefix ‘TT‘ and ‘GA‘ respectively. All prefixes are followed by a number.

 

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Continued on Page 2:

• Legacy Bus Service Prefixes and Suffixes