typical trade approval procedure

7/30/2019 Typical Trade Approval Procedure

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Trade Approval on Dynamic Rail weighing Systems

Trade Approval on Railweight systems can be achieved in two ways. The first is on a concrete slab, the

second is on Ballast. I have detailed below how they are achieved.

Concrete Slab

Install the Rails onto a concrete slab. This is required to meet the tolerances required by trading standards

of +/- 1mm across the rail heads, 1 wagon length either side of the weigh area and reduce movement in the

rail to a minimum, thus allowing us to achieve the required tolerances required for Trade Approval.

The length of the slab is determined by the longest wagon type wheel base you wish to weigh on the

system. The reason for this is you have to be able to sit the longest wagon type onto the concrete slab

either side of the weighing area.

Example. Should the wheel base of your longest wagon (centre first wheel 1st axle, to centre last wheel last

axle) be 15m, you require 15m either side of the weighing area, so that gives us 30m, and the weighing areais 3m, meaning the minimum slam length will be 33m. We would install a 35m slab.

A W&M test consists of the following:

Static test Day 1.

Attending site: Railweight engineer & Local trading standards officer

A static test will be carried out on the system using a calibrated test rig supplied by Railweight

We will need a clear track with no trains during the static test. This will take approx. 2 hours.

Dynamic Wagon Test Day 2 (This could be carried out day 1 depending on the number of wagons in the

test)

Attending site: Railweight engineer & local trading standards officer

We will require the 4 axle wagon type with the maximum number of wagons you operate on site in a rake.

The system will be approved up to that number you put through on the day. You can then use less on the

system and still be approved but you can not use more.

We will require either full wagons on the first day or empty wagons on the first day, either way will be ok.

The next day we will require the same wagon types but the opposite of the first day (i.e. If full first day we

require empty second day)

The wagons will need to be uncoupled one at a time from the rake and slowly rolled over the weighing

device to establish the individual weight of each wagon when uncoupled from the Rake. We will require a

handling crew & locos in sufficient numbers for carrying out these works ( 2 Loco's 1 at the front and 1 at

the rear, and at least 3 ground staff more would be better but no more that 6 ).

The train is then re coupled and must achieve 3 consecutive runs to an accuracy of better than 0.5%.

Approx time for test 1 day.


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Dynamic Wagon Test Day 3

Attending site: Railweight engineers & Local trading standards officer

Same requirement as first day for 4 axle wagon type only opposite of first days test (i.e. If full first day we

require empty the second day)


device to establish the individual weight of each wagon when uncoupled form the Rake. We will require a


the rear, and at least 3 ground staff more would be better but no more that 6 ).

The train is then re coupled and must achieve 3 consecutive runs to an accuracy of better than 0.5%.

Approx time for test 1 day.

System on Ballast

A system can be made Trade Approved on Ballast. However to be able to achieve this you will require a

train of a known weight. The weight of the train will need to be established by a system on a concrete

slab,(as above) this is what is we refer to as the control weighbridge. The test required will be as follows:

Static test Day 1. On the Control Weighbridge (Concrete Slab)

Attending site: Railweight engineer & Local trading standards officer

A static test will be carried out on the system using a calibrated test rig supplied by Railweight

We will need a clear track with no trains during the static test. This will take approx. 2 hours.

Establishing the known train weight on the control weighbridge (Concrete Slab) - Day 1

Attending site: Railweight engineer & local trading standards officer

We will require the 4 axle wagon type with the maximum number of wagons you operate on site in a rake.

The system will be approved up to that number you put through on the day. You can then use less on the

system and still be approved but you can not use more.

We will require either full wagons on the first day or empty wagons on the first day, either way will be ok.

The next day we will require the same wagon types but the opposite of the first day (i.e. If full first day we

require empty second day)




the rear, and at least 3 ground staff more would be better but no more that 6 ). Approx time scale 2 hours

The train is then re coupled and must travel to the site where the system is on Ballast. If it isnt possible to

travel the same day, the train must arrive the next day, no later.


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Dynamic Test Ballast System - Day 2


When the train arrives at the site where the system on Ballast is installed we must achieve 3 consecutive

runs to an accuracy of better than 0.5%. This can take anything between 2 to 5 hours.

Establishing the known train weight on the control weighbridge (Concrete Slab) - Day 3


Same requirement as first day for 4 axle wagon type only opposite of first days test (i.e. If full first day we

require empty the second day)




the rear, and at least 3 ground staff more would be better but no more that 6 ). Approx time scale 2 hours

The train is then re coupled and must travel to the site where the system is on Ballast. If it isnt possible to

travel the same day, the train must arrive the next day, no later.

Dynamic Test Ballast System - Day 4


When the train arrives at the site where the system on Ballast is installed we must achieve 3 consecutive

runs to an accuracy of better than 0.5%. This can take anything between 2 to 5 hours.

The system is now Trade Approved on Ballast

Weather conditions can effect this type of test, i.e. heavy rain overnight whilst traveling between sites, or

heavy snow, both can affect the established weights meaning trading standards may require the known

weights to be re-established, before dynamic tests can be carried out.

I would recommend you have the system re approved as above either once a year, or worst every 2 years

with trading standards.

Please be aware, once the above is complete the system is trade approved to weigh all 4 axle wagons.

However, should you be using more than one wagon type, please be aware once coupled and moving

dynamically, different wagon types could be outside the tolerance of 0.5%. The only way to guarantee all

wagon types are within 0.5% would be to test them all individually as described above.

typical trade approval procedure

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