Rail traction: Correlation
Prices it moves with, and why
Locomotive and rolling stock prices are set on large fleet orders from railways and metros, often years ahead. Steel, copper, traction motors and power electronics are the main costs, while public transport budgets and freight volumes drive demand.
Proxy US PPI: railroad equipment index · monthly, Jan 2006 to Sep 2026There is no free public price for rail traction itself, so this tab uses the closest public series as a stand-in. Read the numbers as an indication, not as the price of this exact item.
What its price moves with
Selected linkRail traction and Steel
Monthly changes 0.12 little or none correlation 12-month changes 0.07 little or none correlation Last 5 years 0.24 monthly changes Lead or lag none No clear lead or lag Price function, Jan 2006 to Sep 2026 Rail traction ≈ 79.0 × (Steel)0.17 R² 0.40 On this fit, a 10% higher steel price goes with a 1.6% higher rail traction price over the long run. Units: index and index, BLS base period.Chart: Rail traction and Steel prices rebased to 100 at Jan 2006, log scale
Both prices rebased to 100 at Jan 2006, on a log scale so equal percentage moves look the same size.Chart: Rail traction price against Steel price, monthly, log scales, with fitted line
Each dot is one month; paler dots are older (2006), darker dots recent (2026); the ringed dot is the latest month. The dashed line is the fitted price function. Both axes are logarithmic.Wagons, bogies, wheels and car bodies are largely steel. The steel index shows little link, because orders are priced years ahead with escalation clauses. Steel costs reach rolling stock prices only slowly, after contracts reset.
little or none co-movement month to month · 249 months Show chartsTraction motors, transformers and overhead catenary use large amounts of copper. The equipment index shows no clear link, with monthly moves correlating at -0.01, because railway orders fix prices long before delivery.
little or none co-movement month to month · 249 months Show chartsElectric trains use transformers and converters to feed their motors from overhead wires. Monthly moves correlate at 0.17 and yearly at 0.29 with the transformer index, a weak link from shared electrical equipment costs.
little or none co-movement month to month · 249 months Show chartsDiesel-electric locomotives burn diesel made from crude oil, so fuel prices affect railway running costs and the case for electrification. The equipment index does not follow, with monthly moves correlating at -0.04, since fleet orders follow long plans.
little or none co-movement month to month · 249 months Show chartsFreight railways, whose revenue depends heavily on hauling coal and bulk goods, are the main buyers of locomotives. The rail freight proxy shows only a faint link with the equipment index, as locomotive orders respond to traffic slowly.
little or none co-movement month to month · 249 months Show chartsTrams and metros use supercapacitors to store braking energy and run short distances without wires. The capacitor proxy correlates at -0.14 monthly with the rail equipment index, so no price link shows; this is a technology link only.
little or none co-movement month to month · 249 months Show chartsHow to read these numbers
Correlation of monthly changes (the number in the coloured pill) compares how much each price moved, month by month, since 2006 or the first month both series exist. It runs from −1 to +1: near +1 the two usually rise and fall in the same months, near 0 there is no link, and a negative number means they tend to move in opposite directions. Above 0.7 is strong, 0.4 to 0.7 moderate, 0.2 to 0.4 weak.
12-month changes compare year-on-year moves, which shows whether two prices share the same cycles even when the month-to-month noise differs.
Price function is a straight-line fit of the two prices on logarithmic scales: price ≈ k × (partner price)β. β is how much this price moves, in per cent, for a 1% move in the partner over the whole period, and R² is the share of the variation the fit explains. Two prices that both drift up with inflation can fit well without any real link, so read it together with the monthly correlation.
Lead or lag checks whether the monthly correlation is clearly higher when one price is shifted by 1 to 6 months.
Correlation is not cause. The reasons on each card explain the economic link; the numbers show how strongly it has shown up in prices. Proxy series are US producer price indexes or related prices and can blur the real link.
Data: World Bank Commodity Price Data (Pink Sheet), October 2026; US Bureau of Labor Statistics producer price indexes, IMF primary commodity prices and US EIA prices via FRED, Federal Reserve Bank of St. Louis, retrieved November 2026. Calculations by this site.