# Why do these two subway trains have a different acceleration sounds? **URL:** \ **Category:** Factual Questions\ **Created:** [May 23, 2024, 10:32pm UTC](https://boards.straightdope.com/t/why-do-these-two-subway-trains-have-a-different-acceleration-sounds/1001994 "2024-05-23T22:32:51Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![themapleleaf](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/themapleleaf/32/14349_2.png) [@themapleleaf](https://boards.straightdope.com/u/themapleleaf)\ **Post date:** [May 23, 2024, 10:32pm UTC](https://boards.straightdope.com/t/why-do-these-two-subway-trains-have-a-different-acceleration-sounds/1001994/1 "2024-05-23T22:32:51Z")
[Here](https://www.youtube.com/watch?v=b1Yuwtpyu4Y&ab_channel=OrionVIII) is an old (long out-of-service) H-series Toronto subway train. On acceleration, it has a distinctive warm, cricket-like sound (@0:35). [Here](https://www.youtube.com/watch?v=h-CHsriZQBI&t=108s&ab_channel=TransitMiranda) is a newer (soon likely to be obsolete) T1-series train. It has a deeper, almost spooky sound when it accelerates (@1:14 and @1:34). Why don’t the newer trains accelerate with the warm chirp of the older model? What causes the much different deeper sound? ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [May 24, 2024, 5:10am UTC](https://boards.straightdope.com/t/why-do-these-two-subway-trains-have-a-different-acceleration-sounds/1001994/2 "2024-05-24T05:10:52Z")
Variable frequency drives vs brake squeak? ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [May 24, 2024, 10:01am UTC](https://boards.straightdope.com/t/why-do-these-two-subway-trains-have-a-different-acceleration-sounds/1001994/3 "2024-05-24T10:01:39Z")
According to this YouTube video comments I found, it’s a set of thyristors at 400Hz driving the traction motors: [![](https://img.youtube.com/vi/1TUXFmWsEB8/maxresdefault.jpg "TTC Southbound Subway - T1 Great Sound") ](https://www.youtube.com/watch?v=1TUXFmWsEB8) [Here](https://www.youtube.com/watch?v=h-CHsriZQBI&t=108s&ab_channel=TransitMiranda) is a newer (soon likely to be obsolete) T1-series train. In Doug Ford’s Ontario, they will be around longer than they should. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [May 24, 2024, 12:51pm UTC](https://boards.straightdope.com/t/why-do-these-two-subway-trains-have-a-different-acceleration-sounds/1001994/4 "2024-05-24T12:51:51Z")
> [@FinsToTheLeft](#): > > In Doug Ford’s Ontario, they will be around longer than they should. They have to save money somehow to pay for the Eglinton line… ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [May 24, 2024, 3:00pm UTC](https://boards.straightdope.com/t/why-do-these-two-subway-trains-have-a-different-acceleration-sounds/1001994/5 "2024-05-24T15:00:42Z")
> [@md-2000](#): > > They have to save money somehow to pay for the Eglinton line… Nah, he’d rather give $225M to The Beer Store instead of the TTC. > **[Doug Ford says beer and wine are coming to Ontario corner stores](https://www.thestar.com/politics/provincial/doug-ford-says-beer-and-wine-are-coming-to-ontario-corner-stores/article_75bed45a-19c4-11ef-8ad5-37ad74b33837.html)** > > There will finally be beer and wine in corner stores after Labour Day thanks to a $225-million payout to the privately-run Beer Store. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 24, 2024, 8:07pm UTC](https://boards.straightdope.com/t/why-do-these-two-subway-trains-have-a-different-acceleration-sounds/1001994/6 "2024-05-24T20:07:59Z")
[Moderating] > [@FinsToTheLeft](#): > > In Doug Ford’s Ontario, they will be around longer than they should. > [@md-2000](#): > > They have to save money somehow to pay for the Eglinton line… > [@FinsToTheLeft](#): > > Nah, he’d rather give $225M to The Beer Store instead of the TTC. A stern reminder that this is FQ. Politicking is inappropriate. ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [May 24, 2024, 8:22pm UTC](https://boards.straightdope.com/t/why-do-these-two-subway-trains-have-a-different-acceleration-sounds/1001994/7 "2024-05-24T20:22:17Z")
Sorry about that, I intended it as an inside joke for other locals rather than politics after providing a potential factual answer. I will refrain from further politicking! ---
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [May 24, 2024, 8:41pm UTC](https://boards.straightdope.com/t/why-do-these-two-subway-trains-have-a-different-acceleration-sounds/1001994/8 "2024-05-24T20:41:39Z")
Copenhagen’s 4th Generation S-Train stock has a distinctive two-tone acceleration sound. It starts as a high-pitched whine, but then after reaching a certain speed it switches to a lower louder pitch. [![](https://img.youtube.com/vi/lZmcOa2PswE/maxresdefault.jpg "[Full HD] S-Tog Train departing at Nørreport station, Denmark") ](https://www.youtube.com/watch?v=lZmcOa2PswE) They run at an odd 1,650 volts DC so perhaps there’s power relays providing some rudimentary gearing to reduce load/stress on the motors when accelerating while also using a more standard motor? The Chicago ‘L’ on the other hand seemed to just go without making much noise at all. That operates on a more typical 600 volts DC.