1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140 
When the fleet focus falls on operational economy, double-decked trailers
Page 60
Page 61
If you've noticed an error in this article please click here to report it so we can fix it.
are increasingly being selected as a fleet option. Steve McQueen assesses the benefits.
They used to be an exception, used by the few for a limited number of freight applications. These days, the inescapable logic that two decks are better than one has led more and more operators to switch to double-decked trailers.
Irish manufacturer Wilson Double Deck Trailers claims the plaudits for introducing the first such trailer in the early 1980s. These days it manufactures a range of doubledeckers, from box vans to curtainsiders, with fixed or moving floor options.
Sales director Ian Wilson accounts for the growing use of the descendants of that early innovation and which types of operations can benefit: "It is used effectively by any operation with a load that cubes out before it weighs out, or one involving products that can be carried in roll cages. As the technology has improved, groupage operators have started using them. Because their freight consignments often vary in size and shape, there are major benefits from using double-deck trailers with moving floor mechanisms!'
So how do the savings materialise? Graham Reeve, operations manager at parcels carrier Initial City Link, is a user of Wilson Double Deck trailers. He says: "We umm'd and ah'd for a while before we switched to double-deckers, but we have now been using them for nine years. We have 80 double-deck trailers and they each carry 43 roll cages. We would be carrying only 28 each time if we used flat trailers, so you can immediately see the main advantages— increased volume, greater stability as well as greater ease of loading and unloading" He also reports savings through a reduction of insurance claims because the ability to use roll-cages has reduced the amount of damaged goods in transit.
Technological improvements have also assisted the success of the operation: "We run the original type of Wilson Double Deck with an external tail-lift, but we also worked with Wilson to design another version with an internal tail-lift which has made the load even more secure. If you can imagine it, the back end of the top-deck floor is cut and forms the tail-lift. We have also just started work on a new concept—a double-decker trailer with a tail-lift at each end. We sometimes have multi-drops on journeys and this will allow us to load the way we need to, without re-adjustment for load stability and weight distribution," adds Reeve.
Technology
Technology has also helped the operations of Scottish groupage specialist Road Movement Services. It has 15 vehicles and the fleet includes two double-deck trailers. One of these has a swivel-deck system, supplied by Boalloy. The other has a moving floor system built by Cartwright and supplied through Transdek.
"Double-deckers will give you a hell of a lot more space. Of the two, the movable-deck trailer is the ideal solution because of the different heights of the consignments we get. Unfortunately we've had some problems with the mechanism and it isn't as reliable as we would like. It is also heavy so you have to watch your payload. The swivel-deck is more reliable, but even that can be a pain because you have to put in the legs to support the upper deck each time," says director Andrew Morren. The savings from using a double-deck trailer can build up into substantial amounts, depending on the distances involved and the modes of travel employed, according to Ian Wilson: The further you travel, the more you will save. If there is a ferry journey involved, the savings go up even more dramatically. We have one client returning savings of up to £50,000 per trailer per year. That's after recovering the cost of the investment. Over 10 years, it expects to save over £500,000 per trailer. If you have 10 trailers that's £5m. In this particular case the company has more than 20 trailers." Sales of double-deck trailers are mainly customer led, says Lawrence Marshall, managing director at trailer manufacturer Lawrence David. He adds that doubledecking creates high stress points. The trailers have to be designed according to a customer's requirements and each deck correctly stressed for its load-carrying requirements, Lawrence David says it builds double-deck trailers using a flexible, allbolted design, which removes "cracking" on the welded structure.
However, one drawback of double-deck designs can be access to the upper deck. The regional distribution centres operated by large retailers often require loading/ unloading into loading docks via the rear of the trailer.
Standard dock levellers don't have enough range to cope with double-decks, so a scissor-lift really needs to be incorporated in the loading bay to get a man with a pallet truck up to the second level. Another option, although only with curtainsided trailers, is to unload without a dock using a masted counterbalanced fork-lift which cal pallets on the upper deck from the sid Andy Inglesden, managing dire Kent-based Dockspeed, agrees that considerations are important specifying a double-deck trailer. Do( is part of the Norfolk Line Group E been using Schmitz-built doubl trailers on refrigerated transport opi for five years, It now has 35. The ree carry Euro or UK pallets and they ATP certified—an important consic for any operator that is taking refri goods abroad.
Mast considerations
Inglesden says: "It's best to use a Ii without a mast inside the trailer, oth( could damage the upper deck or tra as you try to lift pallets out. You check that your client has such a t might become necessary to carry you Inglesden also agrees with Ian about the cost savings that can be a but emphasises that the cash automatically appear on the compar bottom line.
"We get our investment back, ye wouldn't say we get the money ba quickly. The supply chain is always for cost savings and we keep our cu because we are able to pass on sal them. The double-deckers give us a advantage over our competitors."
He sa are constrz consid adds 1 a rul doubl trailer; up to more than ti va lent decker. of decker adds fle "We be able the cus variety of options. For example, alth are known for our refrigerated opf we can also do a lot of ambient busin double-decker beams can also accor hanging garments.
"So we could carry frozen doubli goods at the front, hanging garmen middle and chilled goods at the b; double-decker. Now that's a sigadvantage," says Inglesden.
Contacts
Cartwright: 0161 928 0966 Schmitz Cargobull: 01207 282882 Transdek: 01522 560 029 Wilson Double Deck Trailers: 01762
Potential savings
It is difficult to produce an actual cost per trailer saving. It will depend on the nature of the goods carried and the application. However, a general view is that the maximum you should expect to pay for a double-decker is twice the cost of a single deck. When judging operational benefits, you should consider the additional savings from: • .:.ater volume came.
• )tential fuel savings; • wer ferry costs (pro rata by volume); • ..ss expenditure on tractive units; • less maintenance costs; • fewer drivers.