A rela is an expansionary composition which begins with a vowel but ends with a consonant phrase. A rela has rapid bols and is played in drut laya, helping to create a harmonious chain or musical flow. Many relas are abundant in consonants.

A rela is said to be named from "rel-gadi," which means train. Rela also means flow, like that of a river. A rela itself has a harmonious flow (similar to a train or river) and many relas create some sort of a buzzing sound.

While rela is also an expansionary composition such as kayda and peshkaar, it is not as expansionary as kayda because of the lesser variety of bols compared to that of a kayda. Bols are oftentimes repeated. The "laut-palat" principle is used to improvise the rela, and the same palta may be repeated multiple times in order to create a chain. Additionally, a rela may be played in the form of a rou, which creates a harmonious chain given the fact that a rela has consonant repetition. Common bols used in a rela are “TRKT," "DRDR," "dhinegene," etc. The baya also has a prominent place in rela. Oftentimes, work on the baya is spotlighted in order to show the harmony and flow of the rela. Additionally, because of the disruption caused by playing ke and ge in various frequencies on the baya in a rela, a tabla player may replace all bols on the baya with “ge” in the bhari section and “ke” in the khaali section. In relas with majority consonant usage and just a few vowels such as “dha” and “dhin” in between, the vowels are given more weight and volume in order to balance the composition. 

A rela is usually played after kaydas in a tabla composition and is played in drut laya as the flow created by the heavy and closed consonants requires a fast speed in order to appear appealing. Additionally, the placement of relas is important because they are usually played in the 2nd half of a performance, right after kaydas, and serve as exciting, harmonic, compositions that engage the audience in the form of patterns and speed. 

Sometimes, an emptiness is experienced while playing "ta" in the khaali section of a rela because the harmonious chain is disrupted be a small pause. To combat this, tabla players will play "take" instead. For example, "taSTRKTTK" will become "takeTRKTTK," ensuring that the flow is not disturbed.