It's not a TSW question since it's about real life, but I thought people would be knowledgeable here. Do train crews who are unfortunate enough to operate two strokes like the Class 66/SD40/SD70 wear hearing protection? Maybe the inside of the cabin is well isolated, but surely those ying ying yings must be loud outside. And even if they're not loud enough to damage your hearing, they're surely loud and repetitive enough to be a significant quality of life concern if you're exposed to it 40+ hours a week. Also how accurate are the sound levels in TSW anyway? For example, the BR 185 in the game has a very loud air compressor and cooling fan noise, audible from quite a distance, yet when you stand next to one in real life it's a more subtle mild noise.(though perhaps also drowned out by the sounds of the busy hauptbahnhof) If the real life Class 66 is loud as it's portrayed in the game, and if the cabin is not well isolated, a noise canceling headset(like pilots wear) which you can talk to the dispatch, and also hear AWS and other audible warnings would be handy.
The 66 has a "reputation" IRL among drivers. It really is quite loud and uncomfortable in the cab, and the alternator transition in the mid-speed range (inherited from the SD40-2, apparently) is described as exceptionally harsh by British standards (which usually employ a simple weak-fielding of the traction motors). Ergonomics were decidedly not a factor in its design, aside from inheriting parts of the 58 and 60 cab layout which had received ergonomic consideration, having been designed in the later BR days. The "ying-ying" noise on the 66 is not due to it having a two-stroke engine, specifically, but from the peculiar arrangement of the turbocharger on the EMD engine. As well as being exhaust-driven as per normal, there is a chain drive through a freewheel, so that at low loads (particularly at idle) it acts as a supercharger, which improves scavenging in the two-stroke diesel cycle. To prevent the freewheel from sticking when the engine is left idling for long periods, there is a deliberate instability built into the engine governor, which effectively blips the throttle once per revolution, causing the chain to tension and slacken - and this produces the distinctive noise. It's a whole chain of engineering workarounds. Supposedly the Class 70 is an ergonomic improvement over the 66. It has a better-insulated, air-conditioned cab, making it quieter and more comfortable for drivers. The engine is also a newer model from GE, which doesn't have the "ying-ying" characteristic of the EMD engine, does have improved fuel efficiency, and there is a dynamic braking system which the 66 notably lacks. I think sound level accuracy varies between locos, especially between older and newer models, and is most likely set subjectively. Aside from some of the earliest models (from the TSW1 era), I think most are reasonably set. The Class 47 is a rather obvious outlier, at least for its exterior sounds, which appear quite a lot louder than other locos in-game when that was not the case IRL.
Drivers of Deltics - which were notoriously loud - were issued with hearing protectors. I don’t know whether any Drivers use them in the modern day. I’m not quite sure how it would work with the AWS and other audible in-cab warnings. Potentially I’d imagine the volume of such warning would have to be increased, but that may then be an issue for Drivers who choose not to wear hearing protectors.
Drivers of the Class 66/77 in Germany don’t wear hearing protection. Hearing protection is only worn if you need to enter the engine room while the loco is running. Having worked on 185s, the in-cab sounds in TSW are very accurate, including the maddening electrical buzz. However, that buzz is not audible outside the loco as it is in TSW. Also having worked on German Class 77s, the 66s in TSW are too quiet to my mind. I feel like they sound too tame in TSW. The cab is very noisy and everything rattles.
That's quite interesting to read. How is it then that the 66 is much more popular than the 70? I would've thought with all the benefits it boasts (mainly fuel economy) it would've been the go-to. The only operators that come to mind are Freightliner and Colas.
The noise canceling setup in the headset could be made to only cancel or dampen certain frequencies(like the ying ying) and allow other ones like the AWS. Or much more simply, the AWS could be heard from the headset when the plug is is inserted to the jack, and be heard from the cabin speakers when it is removed.
Simply put, the 70 is a later introduction. By the time it arrived, literally hundreds of 66s had been imported and were in traffic. Freight operators (but not their drivers) like the 66 because it has high availability (especially compared to BR-era diesels like the 47 and 56) and was cheap to buy, so there's a lot of inertia against changing to a different type now. The cost of fuel is one force pushing in that direction, as the EMD two-stroke is actually not very efficient by current standards.
Here in Ireland we have been using the 071 class loco since 1976. It has a 2 stroke EMD 645 2,450hp engine. It's only in the past 10 years that I have noticed some drivers wearing noise canceling headsets while driving them.
For many years, industry (and regulators) just didn't care much about noisy environments below 90 dB. Jackhammer operators, sure, but "trains are loud, what are ya gonna do?" This has changed since the 1990s, under pressure from both regulators and unions (as well as medical research indicating that sounds well below 90 can be damaging with prolonged exposure). This is why for example modern engines like the SD70ACe have sound insulated cabs, and older "thundercab" SD70s are no longer allowed in the lead position, i.e. with a crew on board.
What about the SD40-2? After all it has many scenarios and timetables as the lead in TSW. And perhaps the old SD70 does too
The SD40-2 was built from the earl,y 70s to the early 80s, long before loud noise (or any other comfort considerations) were a thing. Those cabs were called "spartan" for a reason! Heck, they didn't even have air conditioning (some have later had it retrofitted). Then again, SD40s are no longer used for long road hauls: they have been demoted to shunting and local freight.
Aren't they used for long hauls in TSW timetables though? It says things like "Houston to Los Angeles" and the like and there is clearly a SD40-2 in the lead. Of course they could have added them in Barstow for extra braking(dynamic and otherwise) force during the infamous Cajon descent, but again they could have added them to the back of the train, or right behind the modern lead locomotives(though this would take a longer time of shunting) instead of as the lead.
