Are you
sure Julie is used on WMT? The voice is noticeably different from the "Sathern" voice on their Electrostars which I was pretty sure was her.
If so, does she offer a library of accents?
Yes i am 100% sure. It is Julie Berry on both the WMT 170/172/196/230/310/323/350/730 fleet and on the Southern Rail 171/313/377/387/455 fleet. It is the same exact voice. It is well documented that it is her and she has mentioned in an interview that she voices all of the onboard announcements on London Midland and on Southern which confirms it.
Julie Berry is the most widely used voiceover (and also the longest serving one as she was introduced in the late 1970s around 1978 or 1979 as the station platform announcer at many British Rail stations) and she can be heard on all of the past and present trains:
• AGA/NXEA/ONE class 153/156/170/315/317/321/322/360/379/720/745/755
• British Rail stations (Infomat) [removed]
• C2C class 357/387/720
• Chiltern Railways class 165/168/172/MK3
• Elizabeth Line class 315
• EMR/EMT class 153/156/158/170/360
• FCC class 317/319/321/365/377
• FGW/GWR class 387 (only their "this is coach number x of x" announcements at short platforms)
• Gatwick Express class 387/442
• Great Northern class 317/321/365/387/717
• Heathrow Connect class 360
• Heathrow Express class 360
• LM class 150/153/170/172/319/321/323/350
• LNWR class 230/319/350/730
• LO class 315/317/321
• LO class 378 (only their "this is coach number x of x" announcements at short platforms)
• LU 1973 stock
• LU Piccadilly Line stations [removed]
• Merseyrail class 507/508/777
• Southeastern class 375/376/377/395/465/466/707
• Southern class 171/313/377/387/442/455/456
• Stansted Express class 317/379/745
• TFL Rail class 315/360
• Thameslink class 319/377/387/700
• West Midland Metro onboard [removed]
• West Midland Metro stations [removed]
• WMR class 170/172/196/323/350/730
Maybe she does her voice slightly different for different TOCs i suppose. Perhaps some tell her to sound more posh or less posh. But it is the same voice. If you listen carefully to the announcements and compare them you can definitely tell it is her on both WMT and Southern Rail trains.
For some example here is her Southern Rail announcements:
And then here is her WMT announcements:
So it still sounds very similar. I think compared to other voiceovers (like Celia Drummond whose voice changed significantly over the years) i find Julie Berry keeps her voice fairly similar for most of the trains. Maybe a slight difference in the voice she has used but not much. It might also be the different types of speakers on the different trains making her sound slightly different. But it is still her on both.