Will I have a signal on the famous Iron Ore Train (Nouadhibou to Zouérat)?

Expect intermittent coverage. This is the most popular adventure in Mauritania. While you will have strong 4G/LTE coverage at the departure point in Nouadhibou and the arrival in Zouérat, the train travels through the deep Sahara Desert. Signal will be available near towns like Choum, but you should expect periods of no connectivity (dead zones) while crossing the vast empty desert stretches.