MRT algorithm

[choongzhanhong]

Shortest path algorithm works but some discrepancy with online fare calculator.

Steps to replicate:

1. Try Bukit Batok to Bukit Gombak
2. Try Bukit Gombak to Choa Chu Kang.
3. Next, try Bukit Batok to Choa Chu Kang.

For some reason, the sum of Bukit Batok -> Bukit Gombak and Bukit Gombak -> Choa Chu Kang are different from distance of Bukit Batok -> Choa Chu Kang.

[choongzhanhong]

I have written to LTA with the following content:

Hi there. I have a few questions on potential discrepancies on the LTA Fare Calculator (https://www.lta.gov.sg/content/ltagov/en/map/fare-calculator.html)

I understand that when MRT fares are concerned, it takes the shortest distance between entry and exit points. Some queries I have with this:
1) How is the distance calculated? For example, if I were to input the distance between (Bukit Batok -> Choa Chu Kang), I get 4.4km.
Yet, the distance between (Bukit Batok -> Bukit Gombak) is 1.2km, and (Bukit Gombak -> Choa Chu Kang) is 3.3km. These adjacent station distances add up to 1.2 + 3.3 = 4.5km. Why is there this difference?

2) Are there distances factored in for transfer between stations such as Newton from NS21 to DT11 or Bukit Panjang BP6 to DT1? If so, I would like to ask what is the distance?

3) In any case, do you have a list of rail distance between stations? The data available online is in kilometers to 1 decimal place. If there exists data to a more accurate degree, I would like to seek access to it if possible.

Furthermore, I have some clarifications on Concession pass. Let's say a rider has a Train concession pass but not a bus or hybrid one.
If they were to take a ride as such:
Bus ride -> Train Ride -> Bus ride
and the train ride is more than 45 minutes long (let's say from Boon Lay to Punggol), would the second bus ride's fare be counted in a transfer trip or a new trip? 

Thank you for your time!

[choongzhanhong]

Their response:

We received your email of 25 November 2023. Thank you for reaching out to us with your questions and concerns regarding the LTA Fare Calculator and the usage of concession passes for public transport. We appreciate your interest in understanding the fare calculation process and the specific scenarios related to public transport usage.

Regarding your queries about the LTA Fare Calculator, we would like address them below:

1. The distances of stations from origin to destination are summed up and then rounded to the nearest 100m in the system. While the distance for travel from Bukit Batok to Bukit Gombak and Bukit Gombak to Choa Chu Kang is rounded to 1.2km and 3.3km respectively, the total distance from Bukit Batok to Choa Chu Kang sums up to 4.4km after the rounding.

2. We wish to share that the walking distance between MRT interchanges or bus stop to/from MRT is not reflected in the distance results of the Fare Calculator.

3. We note your request for a more detailed list of rail distances between stations. However, we seek your understanding that we are unable to share the master distance data with the public.

We also note your query about the usage of a train concession pass and the fare calculations for a bus ride following a long train ride. Please allow us to share that TransitLink is the managing agency on fare related matters and we have shared your query with them for further review. Transitlink has advised that if a commuter starts his/her journey with a bus ride, then alights at a bus stop to board a different bus service, or even the MRT/LRT, this is considered as making a transfer.

You may refer to this link at https://www.transitlink.com.sg/travel-fares to understand the rules when calculating distance-based fares. You may wish to note on the following that do not qualify as valid transfers:

a) A transfer between two MRT stations that takes more than 15 minutes.
b) Transfer from a bus to another bus of the same service number, or to/from a subsidiary service (e.g. transfers between Bus Services 98, 98A, 98B).
c) Transfer to/from Sentosa Bus, Night Services and Chinatown Direct Services.
d) A Bus Concession Pass, Train Concession Pass or Hybrid Concession Pass is used.
e) A journey that has more than five transfers.

For other specific fare-related queries, you may wish to provide the details of the query and contact TransitLink directly with the contact details below.

TransitLink
E-feedback form: https://www.transitlink.com.sg/eservice/econcession/efeedback.php
Hotline: 1800 2255 663