Many people wonder what are the differences between the use of a ballast surface and the use of a concrete surface. Is one of the solutions definitely better? Will the newer solution on concrete completely replace the ballast track in the future? I will try to answer these questions briefly.

In the ballast surface, we use crushed stone made of volcanic rocks with grain sizes of 31.5 – 50mm. (allowable 22.4 – 63mm). The role of the ballast is to transfer the weight (the impact of the train) from the underside of the railway sleepers to the ground surface or the foundation made of unsorted (0 – 31.5mm) or gravel. The gravel also maintains the shape of the track in plan, stabilizing the position of the sleepers.

In a concrete pavement, this role is most often played by a reinforced concrete slab. In this case, however, no underlays are used, only fastenings on metal plates – in English baseplate. It seems to me the most appropriate to use as the Polish equivalent of the term rib plate, although, of course, these are plates for elastic fastenings.

The installation of the baseplates described above by drilling in the finished concrete slab and the use of glue that secures the screws is called the post drilling method, i.e. the method of drilling after concreting. It looks a bit different in the case of the top-down method, where a material that may resemble sleepers is used – basically 2 half sleepers connected by a metal angle.

What is very important in the case of slab track, the track slab cannot transfer the impact directly from the baseplates to the ground. We must ensure the stabilization of the track slab; in this case it is necessary to make a concrete foundation (first stage concrete).

The details and methods of constructing slab tracks are material for a separate article.

Let us now focus on the basic differences between ballasted and ballastless track.

Of course, the issue of construction costs probably comes to the fore for most readers. In this part, let’s do a quick calculation (in the case of prices, the estimated net prices as of 09.2021).

Rails

We use identical rails in both tracks, so the cost of the rails does not affect the price of the surface.

Let’s assume the 50E1 rail at the price of PLN 3 per 1 kg. The cost of a meter of the current track will therefore amount to PLN 100.

Sleepers and fastenings

The price for a basic baseplate set with fasteners is about PLN 100 per piece (PLN 200 per pair). It is therefore cheaper than in the case of prestressed concrete sleepers PLN 300 (at the same spacing).

However, we must take into account that the assembly of the baseplates requires additional work.

First of all, surveying, because the drilling in the slab must be accurate enough to position the track and maintain the proper clearance. The spacing of the baseplates should also be taken into account.

An additional cost is also drilling in the slab, which requires a team of 4-5 people and appropriate equipment, as well as the cost of glue. Let’s add PLN 50 per meter to the costs. (We will describe the exact construction process in a separate article).

It’s safe to say that the cost of the surface itself, whether counting from the baseplate or from the baseplate up, is more or less the same. The same costs can also be assumed for earthworks. The difference will be primarily in the execution of the layer supporting the track. Before we summarize, let’s calculate the cost of baseplates and sleepers per linear meter of track (we will assume a spacing of 0.6m, so we will divide the cost by 0.6).

Therefore, the cost in baseplates will be PLN 333 / m, and with gluing it will be PLN 383 / m.

The cost of underlays will be PLN 500 / m.

A layer of crushed stone

Let’s assume that 1m of track requires 4 tons of 31.5 – 50mm railway crushed stone at the price of PLN 50 per ton with delivery.

The cost of crushed stone for the execution of 1 m of the ballast surface will therefore amount to PLN 200.

Track plate

In the case of a concrete pavement, let’s assume a track slab with a thickness of 25 cm and a width of 2.5 m. For this board, let’s assume B45 at PLN 400 / m3. The cost of the material itself is about PLN 250. We will assume the cost of making the formwork as 50 PLN per running meter. In addition, the cost of reinforcement and its implementation should be added, let’s assume PLN 100. Total comes out to PLN 400.

Concrete foundation

In the case of a concrete surface under the track slab, we must make a concrete foundation (first stage concrete). Let’s assume a 30 cm thick slab made of B30 concrete and 5.5 m wide. We will assume the price of this class of concrete as PLN 300 / m3. This gives us PLN 495 per running meter of concrete base. Let’s add the cost of formwork PLN 100/m and the cost of reinforcement and its execution PLN 200/m. Total comes out to PLN 795.

Employees

Let’s also add the cost of employees, we will assume PLN 5,000/month per person.

Let’s assume that we have 30 people to make 1 km of ballast track in a month and 90 people to make 1 km of slab track in a month.

Execution of the concrete surface will require more man-hours due to the need to make the formwork, set the reinforcement, concrete both the base and the track slab, and set the track before and after drilling. So we additionally have teams to set the foundation reinforcement, concrete the foundation, concrete the track, set the track for drilling (drilling has already been taken into account), and finalize the positioning of the track.

So, we have PLN 150,000 for a ballast track – PLN 150 per running meter and PLN 450,000 for a concrete track – PLN 270 per running meter.

Equipment

Let’s add the additional cost of machines such as excavators, bulldozers, dump trucks, in both cases we will count PLN 200,000 per month, PLN 200/m.

Let’s summarize the estimated costs:

Of course, our calculations are very simplistic. It can be seen, however, that the cost of a concrete pavement is practically twice as high as that of a ballasted pavement. Even if we exclude labor costs, which may vary in different countries, the difference in materials alone is about PLN 800 / m.

It should also be remembered that the contractor performing the work will also add his margin, so in the case of an order we will be closer to PLN 1,600 for a ballast surface and PLN 3,000 for a concrete surface.

This is the price for the railway surface only, power supply and control are not included.

Is it worth reaching for a slab track solution? Sometimes there is no way out, more in the next article.