This mod updates Swadius' Longer Underground Pipes to be compatible with Factorio .14.x. Since the original had not yet been updated to work with .14, I made the minor changes necessary. Here is the link to the original mod: https://mods.factorio.com/mods/Swadius/Longer_Underground_Pipes

I've also included the author's description below:

This mod adds in extended underground pipes in length of 2x, 4x, 10x, and even 25x. The recipes for these merely involve using multiple underground pipes in the amounts shown and some iron plates IE. 4x Underground Pipes requires 4 underground pipes.