I have mentioned before that the most important factor to the economic potential of Iskandar and Johor Bahru is the extension of Singapore’s MRT to Johor Bahru. I mentioned being skeptical of the claimed timeline years ago. And, in fact, that timeline has proven to be wrong.

Map shows the most sensible place for the first station in JB but that hasn’t been decided yet. Map by Seloloving
MRT link to Johor Baru unlikely before 2020
Hopping onto an MRT train and arriving in Johor Baru is unlikely to be a reality before 2020, as Malaysia has yet to determine a station site for its end of the line.
This Rapid Transit System link was first announced by Singapore and Malaysia in May 2010, and was initially targeted to be ready by 2018.
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Rail construction experts said even if work started today, the line would be completed by 2020 at the earliest. But work is unlikely to start any time soon because no decision has yet been made on where the JB station will be.
And this article is only addressing 1 Johor Bahru MRT station. While that would still be useful. The discussion 4 years ago was starting with 5 stations in Johor Bahru which seems like a much more sensible starting point. Getting to 5 stations by the end of 2021 seems unlikely unless those responsible change the approach and treat this as a critically important project.
The importance of an MRT transportation system interlinking Singapore and Johor Bahru has only grown more critical in the last few years. Transportation issues are going to become increasingly annoying in Johor Bahru as all the luxury condos come online. And getting people into those condos that can afford them is still unrealistic without jobs in Singapore, for which the MRT extension is critical.