How do I change the line style to dash in a scattermapbox plot?

I’m trying to change the line style to dash in a scattermapbox. However, there is no option to do so according to the documentation as line only accepts a dict with properties of width and color.

fig = go.Figure(
    data=[
        go.Scattermapbox(
            name='Railroad',
            hoverinfo='name',
            lat=fcrl_lats,
            lon=fcrl_lons,
            mode="lines",
            line=dict(width=2, color="#ff4931")
        ),
        go.Scattermapbox(
            name='Bike Lanes',
            hoverinfo='name',
            lat=hcbl_lats,
            lon=hcbl_lons,
            mode="lines",
            line=dict(dash='dash', width=2, color="#006699")
        )
    ]
)

I believe this is not yet implemented. You could open a feature request on GitHub if it hasn’t already been done.