Apparently ROG 93s are being assessed for use on the Hanwell Bridge 'trip' stone trains to Dagenham, Purfleet and Harlow.
A 59/66 will bring the huge 4,000t jumbo trains to Hanwell, where they are split into 2 or 3 smaller trains and a 93 will 'trip' the rakes to Essex.
I'm curious what the maximum weight would be for these trains using a class 93 on electric power up Acton bank, considering they are Bo-Bo locomotives and it was suggested their performance on electric power would be comparable to a class 88? Perhaps the two comments quoted below give a rough idea:
between 1:100 and 1:85 rising from Acton Main Line to Acton Wells Jn, for about 450m.
On the continent, 1500-1600 tons are generally specified as the maximum load for four-axle AC locomotives with a 1% (relevant not maximal) gradient. The value depends on the TOC operating the type. This means that a train can usually be started even in poor conditions.
(Anyone) Off topic, out of interest, currently does the (cl. 59 ?) loco that hauled the Jumbo train from the West Country take the front portion forward (and another 'local' one take the rear portion), or is it double-headed 59s and/or 66s from the West Country to Hanwell which are then split up to handle each portion?
The jumbo trains from Merehead or Whatley run with two locos if there are two portions, and then each loco takes one portion forward. This might be a class 59 and a 66 "dead in tow" for example. I think a 66/6 may also capable of pulling a jumbo by itself, but when there are two standard 66s on a jumbo I assume they are working in multi.
As an example, this is a snapshot from three overnight trains in the early hours of Friday 30th May, with the portions dividing at Hanwell Bridge Loops as usual (this sometimes happens in the sidings at Southall instead due to overnight engineering work). The return empty jumbos usually start from Wembley yard.
6A90 20:11 Merehead - Hanwell ran with 66588 & 66536 and 31 box wagons. 66588 worked 6L95 00:44 to Purfleet with 14 wagons, while 66536 worked 6O12 02:30 to Newhaven with 17 wagons.
6A09 23:26 Merehead - Hanwell ran with 66953 and 17 box wagons, a single portion train which formed 6L14 03:12 to Chelmsford.
6A01 22:19 Whatley - Hanwell ran with 59101 & 66416 and 42 hopper wagons. 59101 worked 6L28 04:22 to Dagenham with 24 wagons, and 66416 worked 6L02 03:00 to Chesterton with 18 wagons.
And from yesterday lunchtime (Monday 2nd June):
6A40 08:40 Merehead - Hanwell ran with 59205 & 66416 and 38 hopper wagons. 59205 worked 6M49 13:19 to Neasden with 22 wagons, while 66416 worked 6O45 12:58 to Tolworth with 16 wagons.
6A50 10:26 Whatley - Hanwell ran with 59202 & 59001 and 42 hopper wagons. 59202 worked 6L52 14:27 to Dagenham with 24 wagons, while 59001 worked 6M52 13:42 to St Pancras Churchyard with 18 wagons.
Monday's 6A40 (mentioned above) is seen here:
https://www.flickr.com/photos/d1059/54562969464/ (Photo: Stephen Dance)
6A50 seen in April with a 59 and 66 on the front:
https://www.flickr.com/photos/93293618@N05/54556703124/ (Photo: FEWS FOTS)
The Dagenham portions of these jumbos are usually 24 wagons, hauled by a 59 or 66/6. The early morning 6L28 is planned via Stratford, the afternoon 6L52 via the GOBLIN.
The exact portions on each train can vary, for example 6A40 on 9th April had 18 wagons for Harlow (6L42) plus 16 for Tolworth, as seen here:
https://www.flickr.com/photos/154351395@N07/54455361016/ (Photo: Bob G Foster)
The next day it had 20 for Neasden and 20 for Acton (it can also have a Bow portion of 20 wagons, running as 6L43). That might be one problem with using class 93s - one day there's a portion they can haul, the next day it's going somewhere different and needs a 66.
It's worth bearing in mind that the official max load for a standard 66 between South Tottenham and Woodgrange Park is 2060 tons, and 2085 in the opposite direction. I think this is because of the gradients at each end taking the line up onto the arches - for example when there was a speed restriction through Woodgrange Park a few months ago, it caused problems for loaded sand trains from Dagenham if it was raining, because they couldn't get a good run at the bank. Freightliner's loaded sand trains from Dagenham (6V93 to Theale or 6V94 to West Drayton) usually run with 18 or 19 wagons over the GOBLIN - I wonder how a 93 would cope with that?
If class 93s were used on the jumbo portion workings to Essex, it seems likely that the heavier Dagenham portions would continue to be worked by the 59 or 66/6 that pulled the train from the quarry, with a 93 taking the second portion to places like Purfleet / Harlow / Chesterton / Chelmsford that are under the wires. To be useful on these workings they would ideally need to be capable of hauling 18 wagons on these routes (at least via Stratford). If a typical Bo-Bo electric is designed to restart 1600 tons on a 1 in 100 gradient (as suggested above) they might be able to pull 1800 tons with a clear run up Acton bank. If they go ahead with the trial it will be interesting to see how they perform.
