The -e dative ending is heavily obsolescent. It is almost no longer used in living language.
However, as is often the case (different examples), some phrases that were coined when the old -e ending was still healthy have fossilized and no longer follow the now-current rules:
nach Hause; zu Hause
im Zuge (dessen; der Umbaumaßnahmen; der Neuausrichtung)
im Schutze (der Dunkelheit)
zu Rate ziehen
im Falle eines Falles
Some of these, such as zu Rate and nach Hause, are no longer transparent to language users, i.e. native speakers would no longer recognize them as dative. (Modern spelling even allows the contractions zuhause and zurate.) For others, such as im Schutze, a re-formation (im Schutz) is possible. Which version is preferred in such cases is a matter of taste.
Note that the fossilized phrase im Zuge is restricted to the figurative meaning “in the course (of)“. Someone phoning from within a train is always going to say:
Ja, ich sitze gerade im Zug nach Düsseldorf.
The German constitution (Grundgesetz) provides an interesting example for the fading of dative -e:
Art. 118. Die Neugliederung in dem die Länder Baden, Württemberg-Baden und Württemberg-Hohenzollern umfassenden Gebiete kann abweichend von den Vorschriften des Artikels 29 durch Vereinbarung der beteiligten Länder erfolgen. (…)
Art. 118a. Die Neugliederung in dem die Länder Berlin und Brandenburg umfassenden Gebiet kann abweichend von den Vorschriften des Artikels 29 unter Beteiligung ihrer Wahlberechtigten durch Vereinbarung beider Länder erfolgen.
The former section, regarding what is now Baden-Württemberg, was written in 1949. The latter, regarding what is still Berlin and Brandenburg, was added on occasion of the German reunification in 1990. Although the newer sentence is clearly modelled after the original one, the -e dative sounded too odd to retain it.
