Harold/Henry

Cast

 * Harold as Henry (Harold and Henry's names both start with "H")
 * Hank as Flynn
 * BoCo as Thomas
 * Derek as Diesel (Derek and Diesel's names both start with "D")
 * Bulgy as Spencer
 * Jeremy as Scruff
 * Salty as Trevor
 * Bertie as Victor (Bertie and Victor are both red)
 * Bill as Bill
 * Ben as Ben
 * Trevor as Kevin
 * S.C. Ruffey as Alfred the Loaned B12
 * Donald as Splatter
 * Douglas as Dodge
 * Henry as Bear (from RWS)
 * Isobella as Judge Judy the Diesel
 * Madge as Lady
 * Whiff as Bertie
 * Rosie as Molly
 * Duck as Percy
 * Toby as Ferdinand
 * Colin as Colin
 * Splatter as Lorry 1
 * Dodge as Lorry 2
 * Stanley as Bert (from RWS)
 * Jack as Charlie
 * Alfie as Neville
 * Byron as BoCo
 * Ned as Rex (from RWS)
 * Kelly as Duke
 * Patrick as Duncan
 * Nelson as Rusty
 * Buster as Hiro
 * Bash as Den
 * Dash as Dart
 * Puffa (from TUGS) as Wilbert (from RWS)
 * Flora as Rosie
 * Smudger as Spamcan (from RWS) (Smudger and Spamcan's names both start with "S")
 * Arry as Norman
 * Bert as Paxton
 * Randy Marsh (from South) as Mr. Percival
 * Sharon Marsh (from South Park) as Mrs. Percival
 * Ferdinand as Dennis
 * Oliver as Toby
 * Rocky as Ivo Hugh (from RWS)
 * Gordon as Warrior (from TUGS)
 * James as Bulstrode
 * Caroline as Pinknose
 * The Spiteful Breakvan as The Spiteful Breakvan
 * Hiro as Rocky
 * D261 as James
 * Elizabeth as Elizabeth
 * Hector as Cranky
 * Diesel as Sixteen (from RWS)
 * The Foreman as Sir Topham Hatt
 * Thomas as Harold
 * Emily as Madge
 * Percy as Jeremy
 * Belle as Mavis
 * Diesel 10 as Mallard (from RWS)
 * Old Stuck-Up (from RWS) as Johnny Cuba (from TUGS)