The first reports gave ten dead; by evening The Guardian and the BBC reported at least 68 killed, many injured, fifteen in grave danger. The Iryo carriages overturned and rolled down the embankment; one caught fire; a long section of rail, as the pictures show, speared through a carriage. According to Hungarian Conservative, military emergency units and firefighters were sent, hospitals in Toledo and Alcázar de San Juan postponed scheduled operations, and the line between Madrid and Seville was closed. Pedro Sánchez declared three days of public mourning. This is Spain's second major collision this year, and the third deadliest on its railways in fifty years.

Óscar Puente, the transport minister, set out the cause thus: first the computer failed, then a man erred. When the system fails, a control centre in Madrid that keeps watch day and night takes command; and that centre, the minister says, by a decision he himself called inexplicable, ordered the trains to move again, with no speed restriction imposed. Seventeen minutes passed between the halt and the impact. The controller himself is said to have been questioned by investigators. Whether the line's automatic safeguards were working, had failed, or had been overridden, the reports do not say. That was the first thing to ask; so far there is silence.

Nothing in a work is inexplicable. We must seek, as Tacitus advises, to know "not only the chances and outcomes of events, which are mostly fortuitous, but their reason and causes." A machine failing is chance; we know machines fail. But when the machine has failed, a man should grow slower, not bolder. Here the opposite was done: the eyes of the line were blinded, and at that very moment the order was given to run.

No general sends a column at the double through an unknown pass when his scouts have reported nothing. The controller in Madrid did not see the line; he saw a board, and the board was mute. At the Portus Iulius I trained my rowers through a whole winter before I led them against the enemy; I say the same of those who sit in the centre: they must be drilled in a mock storm, not a real one. And I ask what the reports leave out: when a private company and a public one run on the same line, under one control centre, who alone answers for it? A work with two masters often has no keeper at all.

The faster the line, the heavier the watch. I brought water into the city, but I had not finished the work when I brought it in; I maintained a crew of 240 skilled men to guard the aqueducts, which I left to Augustus when I died, and he made it public. A public work is never finished; it is kept, every day. Two collisions in one year are not Fortune's doing, but the system's.

The remedy is at hand, and it is not new. First: when the signals fail, no train moves except at walking pace, until the line has been seen to be clear. Next: let one magistrate be set over the line, with authority and with a name, who bears the penalty when there is error. Then: let the minister walk the line on foot, as I went through the sewers by boat. Last: let the inquiry be finished within the year and posted openly for the people, not argued over at the elections. The parties suspended their canvass, Vox carried on; but the dead are not a speaker's platform. Speed without a watch is no public work, but a trap built of bronze and iron.

M · AGRIPPA, SON OF LUCIUS, THREE TIMES CONSUL, INSPECTED THIS