Rail transportation could be expected to form a key part of the case for bringing the MMRCV into service in London. As part of the MMRCV project, loading and unloading trials were planned at the Waste Recycling Group (WRG) site at Hendon in November 2007. There were a number of issues identified during the site visit that prevented the trial from taking place. These were:
Physical assessment
Unloading/loading of containers
The gantry crane cradles have fixed twist lock positions specifically designed for the size of containers used at the WRG, Hendon operation.
Hendon gantry crane positioned to demount the MMRCV container
19 Costs taken from study commissioned by TfL - Peter Brett Associates (2007): MMRCV loading and unloading, Review of Handling Systems for London’s Canal network.
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The container and twist lock dimensions do not conform to the ISO or CHEM standard of the MMRCV container so the container could not be off loaded, halting the proposed trial.
Table 16: Comparison of Rail and MMRCV container dimensions
Container Length Width Height
WRG Rail Container 5.9m 2.26m 2.6m
MMRCV 5.0m 2.5m 2.5m
The distance between the twist lock positions on the MMRCV container is 400 cm length and 233 cm width. The difference in width between both types of container twist lock positions is only 6 cm.
Therefore, if a cradle was manufactured to the MMRCV container size then there is no reason why the MMRCV containers could not be off loaded in the same way as existing WRG containers.
Loading containers to rail carriages at WRG Hendon
The method used to attach the containers to a railway carriage is a very simple mechanical twist lock arrangement. The width of the twist lock centre points on the MMRCV container could be moved to fit a railway
carriage, with additional twist locks welded to the railway carriage at the correct length positions. However, modifying containers to fit railway carriages would mean that they weren’t CHEM standard compliant and would require further
modifications for road transport
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via skeletal trailer.
Feasibility
The current operation at Hendon features a Waste Transfer Station (WTS) which handles waste deposited by up to 10 RCVs at a time. This waste is compacted into rail containers with an average payload of about 15 tonnes.
The containers are sized to utilise the maximum bed length on a standard railway carriage of approximately 20 metres. The containers are approximately 6 metres in length and 3 are attached to each railway carriage. The total payload per carriage is, therefore, 45 tonnes and a train is usually 20-22 carriages long which equates to 900 tonnes–990 tonnes of waste being transported per train.
The MMRCV containers, at 5 metres in length (or the projected 6 metres for the
commercially-produced unit) have a capacity per unit of between 9 and 10 tonnes of waste.
Assuming 3 containers per carriage on a 22-carriage train this would give a total payload of 594-660 tonnes of waste. For loading there will be necessary modifications to the 6m
MMRCV containers and the rail trucks to carry three per truck, as is the current practice with WRG's own containers. This is not seen as major obstacle by the manufacturer and a suitable rail loading version of the MMRCV could be specified from these MMRCV prototype trials.
An alternative option would be to produce MMRCV containers slightly shorter than the 5 metre prototype so that 4 units could be carried per rail carriage. This would reduce
individual payload to around 8 tonnes per container but increase overall train payload to 704 tonnes (on 22 carriages) – see Table 17. With all MMRCV options either additional
carriages, and/or trains, would be needed to move comparable waste tonnages to those currently achievable with the WRG system.
Table 17: Summary of current WRG payloads vs projected MMRCV payloads Container Payload /
container
One of the particular advantages of an MMRCV operation is that it eliminates the need for the Waste Transfer Station (WTS) and the additional handling. Waste arriving by MMRCV is already containerised cutting out the double handling element of the operation. MMRCV containers would ideally be loaded straight onto rail carriages, removing the need for a WTS, which would deliver capital and operating cost savings.
A full financial feasibility study would be needed to assist in understanding the cost implications of the MMRCV payload deficiency and infrastructure changes against the
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potential savings of replacing the WTS. However, the following desk case study illustrates the potential costs and savings.
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Desk Case Study: Economics of rail transport for MMRCV
There are potential financial savings in transporting residual waste in MMRCV containers to landfill sites. The estimates in Table 18 have been calculated using data from a recent study (Longley-Cook 2007) and are based on taking residual waste from Hendon in North London to Calvert Landfill site in Buckinghamshire (about 170 miles or 272 km round trip) by rail20. By road this is about a 104 mile round trip (168km).
Table 18: Estimate of costs of loading MMRCV containers directly onto rail freight wagons at Hendon for transport to Calvert Landfill site, Buckinghamshire
Waste Transfer Station (WTS) Costs
Annual capital costsa £350,000
Variable costs £630,000
Total £980,000
Annual tonnage 227,000
WTS cost per tonne £4.32
Rail transport costb £6.94
Total Cost £11.26
MMRCV Cost per tonnec
Load 10.0 tonnes £10.41
Load 9.5 tonnes £10.96
Load 9.0 tonnes £11.57
a. Based on Waste Transfer Station with a nominal capital value of £2million licensed to process 250,000 tonnes of waste per annum.
b. Source: William A Longley-Cook (2007) MSc Dissertation on Rail Transport (Data originally sourced from SRA and WRG).
c. Directly loaded onto train and transported from rail siding to landfill site.
The desk study indicates that direct transfer of residual waste by the MMRCV to rail
carriages for transport to landfill sites outside London is likely to be similar or less cost than using a Waste Transfer Station. With a total of 790,000 tonnes of waste21 (in 2005) of waste being transferred to landfill sites outside the capital by rail, the estimated savings with a load of 9.5 tonnes loaded into an MMRCV container would be £237,000 pa and for 10 tonne load this would be a saving of £671,500 pa. For lower volumes of waste the rail costs would be higher. The road-only cost equivalent for taking 20 tonne loads is between £12.10 and
£13.73 per tonne plus operator’s profit margin (typically 0.24p).
20 The estimates for the waste transfer station may not reflect the current value or operating costs of the facility being operated in Hendon by WRG – the figures are for illustration only.
21 Source WRG