D365
Veteran Member
- Joined
- 29 Jun 2012
- Messages
- 11,460
There's a few threads discussing why these noises are made on AC motored units. I should have a few bookmarked somewhere if there's any further interest.
Siemens operate the traction converters slightly differently in AC and DC supply areas. The way the 3 phase variable frequency AC is produced is complex, and this is the noise you hear. It isn’t caused by the motors, it is caused by the production of the voltage going to the motors.On the noise topic - don't know if it's just where I've been stood in relation to the train, but my observations of Class 700's on Thameslink (which I'm assuming are similar mechanically to 707'), are somewhat confusing.
On DC, they seem to emit the UFO sound that other electric desiros do. However, on AC they sound more like an Electrostar with a single continuous tone.
Logically the motors would sound broadly the same regardless of power supply, is there more to it or are my ears playing tricks on me?
I've heard it referred to that outside the forum a few times, it is fairly similar to the stereotypical noise a flying saucer would make in people's heads, I can't see that going away!I do wish people wouldn’t call it a ‘UFO noise’ though, I don’t think anyone has actually recorded one of those...
707019+707020 appear to be entering service this evening on 2R49, 1715 Waterloo-Waterloo via Richmond and Brentford.
I'm fairly sure I saw 7017 working the Weybridge road on Monday.Ah good, another couple to hunt down on Friday
Any news on 707017 entering service (with 018 entering service last Saturday)?
Are all the diagrams that are due to be served by 707s now switched over?
Many thanks. Any idea what the delay is delivering the remaining four units? Any truth to the rumour that they’re being repainted?Not just yet, 27 are required for the full service, with only 26 currently in the UK and available for service.
Many thanks. Any idea what the delay is delivering the remaining four units? Any truth to the rumour that they’re being repainted?
Not sure what you are replying to, but the lease expiry dates for the 455, 456, 458 and 707 fleets are as posted above. That is what is written in the franchise agreement.Eh? Arent all of 455/6, 707, and 458 going in 2019 with 701s
ok...thats odd. Never mind
Why is it odd? Bombardier aren't going to deliver them all instantly, so you need to phase out the existing fleet. Removing the smaller (and in the case of the 707s more expensive to lease) fleets first makes operational sense.ok...thats odd. Never mind
There's another delivery this weekend, the normal Friday night path.
Out of the current suburban stock, their lease expires first, so I highly doubt they will be repainted. (707 lease expires December 2019, 458 lease expires April 2020, 455/456 lease expires December 2020)
Why is it odd? Bombardier aren't going to deliver them all instantly, so you need to phase out the existing fleet. Removing the smaller (and in the case of the 707s more expensive to lease) fleets first makes operational sense.
You are right in fact they are actually all rather close together !. If none of the leases are extended then I would say Bombardier have a year or a bit less after the 707s go off lease to when the 455, 456 & 458 go off lease. Now I expect Bombardier will be planning to deliver the replacements for 455, 456 & 458 over more than a year - more than a years work there I assume ?. That would mean some being delivered before all the 707s should go off lease. That makes me think all 707s might get stored / mothballed in advance of the December 2019 deadline. Especially the first few surplus 707s might go into store nearer/before December 2018 !. Thats my conjecture.
I think you mean 8/12/2020. There's also a one year contingency so Dec 2021 is the absolute deadline to avoid a franchise breachThe planned introduction profile is in the franchise agreement, page 434. The first 2x 10 car trains should be in service by 15/09/2019, and the last 6x 5 car trains should be in service by 08/12/2019. Provisional, obviously, but not that much more than a year if it all goes to plan.
Yes, good spot. Fixed now, thanksI think you mean 8/12/2020. There's also a one year contingency so Dec 2021 is the absolute deadline to avoid a franchise breach
Nope. There’s one mainline diagram in particular which hasn’t switched over yet, and it’s my train home on a Thursday evening from Kingston!Are all the diagrams that are due to be served by 707s now switched over?
There will be, don't think they have gone over to 707s yet though. Should be:Are any 707s currently scheduled on the Epsom line? There was one until the December 2017 timetable change.