Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering
Transport Technology



I. de Jong Onderdelenbeschikbaarheid en voorraadnauwkeurigheid bij NedTrain Services BV
Masters thesis, Report 2004.TL.6895, Transport Engineering and Logistics.


At NedTrain Services, 'service level at te desk' and 'stock accuracy' are being used as performance indicators. The target service level is 93%. In July 2004 the servicelevel was calculated at 92%. The 'stock accuracy' has it's target at 95%. Currently it is calculated at 88%. This research analyses why both KPI's are not at their desired targets. Next it investigates how both KPI's can be brought at their targetlevel.

NedTrain Services supports railtransport companies with the whole product life cycle of their equipment. NedTrain Services takes care of the technical maintenance, security checks, the cleaning of the equipment and delivers 24/7 emergency support. This assignment was done at NedTrain Services, at the Material Management department of 'Regio Randstad Zuid'.

Maintenance takes place at five maintenance workshops and a lot of support workshops. A store is available at all mainenace workshops. They store up to 10.000 different parts with a total value of approximately 9 million euros. The 12 support workshops of the 'Regio Randstad Zuid' store aproximately 80 to 400 parts each. National there are 42.000 parts stored, valued at about 44 million euros.

KPI 'Service lever at the desk'
The KPI 'Service lever at the desk' calculates the availability of spare parts at the frontdesk of the store in Leidschendam. It is defined as: The KPI 'Service level at the desk' is accurate enough to measure the availability of spare parts. There is a good argumentation for the target of 93%.

When the store can not deliver the amount of spare parts a 'nulbon' is created. During seven weeks the causes of 'nulbonnen' are measured. In figure 1 the results are stated.

The KPI 'Service level at the desk' can be brought at it's target of 93% by taking the steps as depicted in figure 2. These actions can be taken by the region. By increasing the 'Service level at the desk' to it's target savings can be accomplished , valued at 94.000,euros. The expected costs will be at 5000,- euros.

KPI 'Stock accuracy'
The KPI 'Stock accuracy' measures how the amount stock in the store compares to the amount of stock noted to the computer system. The stock accuracy is defined as: A couning list is a list which contains all the spare parts that are planned to be counted. One line on the list represents one spare part.

The KPI 'Stock accuracy' is easily manipulated an can only be used with a number of strict constraints. The target of 95% is randomly chosen.

Incorrect stock count are caused in four different ways:
Some groups of artikels contain more errors than others: Incorrect stock count indirectly costs 91.500 euros at Leidschendam on a yearly basis.

The cost for the loss of parts cost at Leidschendam in 2004:
This is a bandwith of 17% of the value of the stock.

These costs are not clear for the company.

To reduce the number of incorrect stock count the next steps should be taken: In general
NedTrain has a culture of islands. All four regios work on there own way. Because of this culture each others activities are not understood.

NedTrain has a highly layerd structure. From the bottom up, you get head of the store, the material manager, and the head of the logistics department. There has to be a lot of conversation to get at one line

Because of the amount of reports it is easy to loose overall picture.

It is recommended to

Reports on Transport Engineering and Logistics (in Dutch)
Modified: 2005.03.09; logistics@3mE.tudelft.nl , TU Delft / 3mE / TT / LT.