# Why were the smokestacks on old time steam locomotives funnel-shaped? **URL:** \ **Category:** Factual Questions\ **Created:** [July 5, 2007, 2:53am UTC](https://boards.straightdope.com/t/why-were-the-smokestacks-on-old-time-steam-locomotives-funnel-shaped/410556 "2007-07-05T02:53:30Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![stuyguy](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@stuyguy](https://boards.straightdope.com/u/stuyguy)\ **Post date:** [July 5, 2007, 2:53am UTC](https://boards.straightdope.com/t/why-were-the-smokestacks-on-old-time-steam-locomotives-funnel-shaped/410556/1 "2007-07-05T02:53:30Z")
We’ve all seen photos of Civil War-era steam locomotives. They have these huge funnel-shaped smokestacks. It wasn’t always like that. Early, early steam locomotives had straight-pipe smokestacks. Why did they change to the cone-shaped design? ---
**Author:** ![Labtrash](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/labtrash/32/528_2.png) [@Labtrash](https://boards.straightdope.com/u/Labtrash)\ **Post date:** [July 5, 2007, 3:27am UTC](https://boards.straightdope.com/t/why-were-the-smokestacks-on-old-time-steam-locomotives-funnel-shaped/410556/2 "2007-07-05T03:27:11Z")
Spark arrestors, I think. I’m just guessing until someone more qualified comes along. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [July 5, 2007, 3:33am UTC](https://boards.straightdope.com/t/why-were-the-smokestacks-on-old-time-steam-locomotives-funnel-shaped/410556/3 "2007-07-05T03:33:04Z")
The conical design is the [Radley-Hunter centrifugal spark arrester](http://www.saunalahti.fi/~animato/3003/3003ah.html) that was used on wood fuel locomotives. Coal fired locomotives used a straight stack.