Google Maps may be introducing subway station layouts to its mobile interface. A Reddit user uploaded a screenshot yesterday which displayed the new graphic for the New York City Pennsylvania Station layout, but the person claims it’s not yet accessible on the desktop version.

Further comments indicate that this also affects various stations in Japan including Tokyo Central, Yokohama, and Osaka. However, these stations have reportedly had visible layouts in place for a while now, so we’re left wondering about how Google is rolling this out.

Another Redditor says that these layouts have been showing up in the Washington D.C. subway system for several months now. It’s possible that these stations are basically a “soak test” to gauge reaction to it, and that more cities will be added soon, though we’re yet to discover any other areas where the feature is in place.

If this UI is on its way soon, it might be an idea for Google to prioritize the London underground system — ‘cos that thing is a hot mess.