Philadelphia theater is experiencing a veritable Maury Yeston festival: This weekend, the composer and lyricist will be represented locally by two shows, the Walnut Street Theatre’s Phantom and Titanic at the Merriam.

Both musicals come to us with intriguing background stories about the state of theater and media in the 1990s. Yeston’s Phantom was trumped by the Webber version, and the result is that the better show — Yeston’s — has yet to see a Broadway production. Titanic’s story is happier, though its start was rocky. Pre-opening publicity suggested the show was in trouble, the initial reviews were lukewarm and Titanic showed every sign that (like its namesake) it would capsize early and expensively. Enter an angel in the form of none other than Rosie O’Donnell, who loved Titanic and promoted it, building positive word-of-mouth in the crucial early weeks. O’Donnell’s initial help allowed the musical to hold on — but it was James Cameron’s movie and the ensuing Titanic frenzy that clinched the stage show’s success. The show found an audience, it won the Tony Award for best musical, and ultimately some of its early critics admitted they had misjudged the piece.

That reviewers were confounded is a measure of how often Titanic the musical suprises us. Unlike the sudsy Cameron blockbuster that consistently takes the low road, Yeston and librettist Peter Stone are after something weighty. Special effects are minimal, and the ship is rarely seen in anything larger than fragments. More daringly, the piece is an ensemble work with no single story line given special prominence. We don’t have a particular object of sympathy, but that is precisely the point — the scale of the real Titanic disaster is much grander than any personal tragedy could embody. Yeston’s score is similarly high-reaching, mostly eschewing conventional songs in favor of lengthy concerted ensembles of nearly operatic scale. Not all of Titanic works, but even when it doesn’t it’s a work of stature and seriousness.

So let us be grateful to our local theaters for producing these two Yeston works and hope that the hat trick is soon completed with a revival of Nine, the Yeston-Kopit show that (rivaled only by Sondheim’s Sunday In The Park With George) may be the greatest American musical of the 1980s.