Question: What singer was inducted into the Rock and Roll Hall of Fame in April 2014 and did guest vocals on the Old Train album?

Context paragraphs:
Old Train: Old Train is the fourth album by the progressive bluegrass Maryland band The Seldom Scene.  The album offers the group in their original lineup and features their trademark songs "Wait A Minute", "Old Train" and "C & O Canal".  The record is a mixture of progressive, traditional bluegrass and folk material and also features guest musicians as Ricky Skaggs on violin or Linda Ronstadt on vocals.

Long Time... Seldom Scene: "Long Time... Seldom Scene" is The Seldom Scene’s first-ever release with Smithsonian Folkways.  "Hickory Wind" is a homesick ballad that features the vocals of longtime friend of the Scene, Emmylou Harris, who originally recorded the song on her ‘Blue Kentucky Girl’ album in 1980.  “Wait a Minute” is a fresh take of a song originally recorded for 1974’s Old Train album and includes founding member John Starling (vocals) and guests Rickie Simpkins (fiddle) and Chris Eldridge (guitar), son of founding member Ben Eldridge (banjo).

Roy Bittan: Roy J. Bittan (born July 2, 1949) is an American keyboardist, best known as a member of Bruce Springsteen's E Street Band, which he joined on August 23, 1974.  Bittan, nicknamed The Professor, plays the piano, organ, accordion and synthesizers.  Bittan was inducted as a member of the E Street Band into the Rock and Roll Hall of Fame in April 2014.

Doc Pomus: Jerome Solon Felder (June 27, 1925 – March 14, 1991), known as Doc Pomus, was an American blues singer and songwriter.  He is best known as the lyricist of many rock and roll hits.  Pomus was inducted into the Rock and Roll Hall of Fame as a non-performer in 1992, the Songwriters Hall of Fame (1992), and the Blues Hall of Fame (2012).

The Midnighters: The Midnighters were an American R&B group from Detroit, Michigan.  They were an influential group in the 1950s and early 1960s, with many R&B hit records.  They were also notable for launching the career of lead singer Hank Ballard and the worldwide dance craze the Twist.  Between 1953 and 1962 the Midnighters had almost two dozen hits on the U.S. Pop & R&B charts.  Their big hits included the million-selling Billboard Top 10 pop hits "Finger Popping Time" (for which they received a 1961 Grammy Award nomination), and "Let's Go, Let's Go, Let's Go".  The Midnighters also had 13 Top 10 R&B hits, including three that reached number 1.  Their Top 10 R&B hits included "Work with Me, Annie", "It's Love Baby (24 Hours a Day)", "Annie Had a Baby", "The Hoochi Coochi Coo", "Teardrops on Your Letter", "Get It", "The Float" and "Nothing but Good".  They received the Rhythm and Blues Foundation's prestigious Pioneer Award in 1992 and were inducted into the Vocal Group Hall of Fame in 1999.  The group's lead singer, Hank Ballard, was inducted into the Rock and Roll Hall of Fame in 1990.  The Midnighters as a "group" were inducted into the Rock and Roll Hall of Fame on April 14, 2012.

Rock and Roll Hall of Fame: The Rock and Roll Hall of Fame, located on the shore of Lake Erie in downtown Cleveland, Ohio, recognizes and archives the history of the best-known and most influential artists, producers, engineers, and other notable figures who have had some major influence on the development of rock and roll.  The Rock and Roll Hall of Fame Foundation was established on April 20, 1983, by Atlantic Records founder and chairman Ahmet Ertegun.  In 1986, Cleveland was chosen as the Hall of Fame's permanent home.  Since opening in September 1995, the "Rock Hall" – part of the city's redeveloped North Coast Harbor – has hosted more than 10 million visitors and had a cumulative economic impact estimated at more than $1.8 billion.

Rock &amp; Roll Hall of Fame Covers EP: Rock & Roll Hall of Fame Covers EP is EP compilation by American rock band Red Hot Chili Peppers, released in 2012 through iTunes as a digital-only download.  The band first announced the EP through their website on April 19, 2012 with the title "We Salute You", although it was changed on the date of the release.  The EP consists of six cover songs, live and in the studio, of previous Rock and Roll Hall of Fame inductees all who influenced the band.  The EP was released to commemorate the band's own induction into the Rock and Roll Hall of Fame in 2012.  All six songs have been previously featured on other releases by the band.  Four of the six tracks had never been released digitally before.

California 37 (album): California 37 is the sixth studio album from California rock band Train.  The album was released on April 13, 2012 through Columbia Records.  It is the last Train album to feature drummer Scott Underwood before his departure in 2014 and the last recorded as a three-piece.  It was preceded by the lead single "Drive By" on January 10, 2012.

Linda Ronstadt: Linda Maria Ronstadt (born July 15, 1946) is an American popular music and country music singer.  She has earned 11 Grammy Awards, three American Music Awards, two Academy of Country Music awards, an Emmy Award, and an ALMA Award, and many of her albums have been certified gold, platinum or multiplatinum in the United States and internationally.  She has also earned nominations for a Tony Award and a Golden Globe award.  She was inducted into the Rock and Roll Hall of Fame in April 2014.  On July 28, 2014, she was awarded the National Medal of Arts and Humanities.

Music of Ohio: The Rock and Roll Hall of Fame and the Rhythm and Blues Music Hall of Fame are located in Cleveland, Ohio.  Ohio musicians inducted into the Rock and Roll Hall of Fame include, The Isley Brothers (from Cincinnati) in '92, The Moonglows (from Cleveland) in 2000, The O'Jays (from Canton) in '05, Chrissie Hynde (from Akron) of The Pretenders in '05, and Bobby Womack (from Cleveland) (d.2014) in '09.  This state is also the home of four major symphony orchestras which are located in Cleveland, Akron, Cincinnati, and Dayton as well as a "pops" orchestra, the Cincinnati Pops.

Supporting paragraphs: Old Train Linda Ronstadt
Answer: Linda Ronstadt