This episode represents the second appearances by both Michele Greene and Danielle Nicolet on the show, but neither is actually in a recurring role.

This episode, which emphasizes Al and David far more than typical, has an unusually high degree of autopsy and open cadaver activity even for CSI.

Nick is implied as second in command on the graveyard shift -- When Catherine is called away, she calls him to act as acting supervisor. Since he is the only other CSI member of the original cast, this makes perfect sense.

David, the longtime assistant ME, performs his first solo autopsy in this episode.

Title: The Gone Dead Train

The Gone Dead Train is one of eight known recordings made in 1932 by blues artist King Solomon Hill. A cut of song is played briefly in the episode, and Hill's name is mentioned as the artist.

Raymond: Dead Shrimp Blues. Robert Johnson. Recorded Friday, November 27th, 1936, San Antonio, Texas.
Al: The Gunther Hotel, three blocks from The Alamo.

Robert Johnson is considered by most to be one of the greatest acoustical guitar men who ever lived. Most of the famous modern guitar players and quite a few musicians have acknowledged his influence -- Muddy Waters, Bob Dylan, Eric Clapton, Ted Nugent, Jeff Beck, Johnny Winter, Jimi Hendrix, as well as the influential members of quite a few major bands -- The Beatles, The Rolling Stones, Led Zeppelin just to name a few. While he recorded for only a short while, dying in 1936 at only 27, and using very primitive recording techniques, his blues playing has survived the test of time. Many of the great guitar players acknowledge that most of them picked up on and refined techniques he created in the first place. His short life and early death at an otherwise unremarkable country crossroads have only contributed to the legends and myths surrounding him, one being that he sold his soul to play that well, and the Devil came to collect. The movie Crossroads is a riff on that aspect of his life story, and in the Coen Brothers film O Brother, Where Art Thou?, the Tommy Johnson character, picked up by the protagonists at a crossroads, is a riff on Robert Johnson.

A mission at The Alamo was the location of a classic, key battle in the history of the state of Texas, in the USA. When parts of Texas, then under the control of Mexico, revolted, they quickly defeated all Mexican forces inside Texas' boundaries. The Mexican government, however, was unwilling to accept the independence of Texas, and marched into Texas to reclaim its lost territory. In the way was a small mission at The Alamo, which had been fortified with a few captured cannon, and a couple hundred men and their families. The commander of the Mexican forces, Santa Anna, laid siege to the mission for about 12 days, before the mission fell, and almost all the men were killed, including, of particular note, James Bowie (as in "Bowie Knife") and Davy Crockett. The news of its fall rallied the Texians in revolt, however, and, a few weeks later, led to the Battle of San Jacinto, where the rallying cry, "Remember The Alamo!" became a cultural meme. When Santa Anna was captured at that battle, he not only had to surrender but also to cede freedom to Texas. The battle has since been the subject of a number of movies and become a substantial meme, especially in Texas itself.

Hodges: That would be the main course. Although it was too small for me to identify the species, I think we know it's pretty obvious. Babe... (pauses, no recognition) Wilbur?

Babe was a book made into a classic 1995 children's film about a pig that aspires to the duties of a sheepdog, and has sufficient charm and wit to have great appeal for adults as well. The gist of the story ties to the young babe's desire to be more than "just a pig" and his subsequent training and entry into a sheepdog contest by the farmer who owns him, after his prize-winning dog is injured. The animals all spoke among themselves (but not in a manner understood by humans) and had a wide array of odd but reasonable characters, including a duck who aspired to the duties of a rooster, so as to avoid becoming dinner. The movie was an unexpected popular hit, was nominated for a number of Academy Awards, including Best Picture and Best Director, and spawned a less well-received sequel.
Wilbur was the hyper-intelligent pig on the classic 1960s rural TV farce Green Acres. While, like Babe, Wilbur was a "real" pig, he was treated as a family member (and a young boy) by his owners as well as most of the local farming community, spoken to as though he fully understood English, and generally acted with far more understanding than would be expected. Many also acted as though they fully understood his various snorts and grunts in response.

Greg: First rule of Diet Club...
Riley: ...Don't talk about Diet Club.

Fight Club is a book made into a classic 1999 film starring Ed Norton and Brad Pitt, about an underground fighting club that grows into a revolutionary social movement. There are a number of rules for the club and the manner in which the fights take place. The first of these is "The First Rule of Fight Club is, Don't Talk About Fight Club", which is how it stays underground. The advertising campaign for the movie, aimed at keeping one of the key secrets of the story and plot undiscussed and thus unrevealed to those who hadn't seen the movie, emphasized the First Rule, and turned it into a widespread meme.

Frank: (looking at Al and Ray) Got it, Ebony and... Ivory.

Ebony and Ivory is a very popular duet from 1982 written by Paul McCartney and sung by McCartney and Stevie Wonder. On the simplest level, the song is about the black and white keys on a piano, but the overall theme of the song is racial harmony and coexistence.

Brass: You know, I'm a little confused, Batman. Was your mission to avenge your wife's death or rid Gotham of scumbags?

Gotham City is the usual operating environment of Batman.
Batman is an exceedingly well-known comic book hero (also movies and TV), a costumed vigilante whose main motivation for his actions is the murder of his mother and father when he was a child.